Question Summary:
The Shaykh told my family members that it is not necessary to fast or pray. What should I do?

Question Detail:

I am born to Muslim family and I love my religion and have full faith. 
I used to live in one of the countries in Asia before coming to Australia. I was a refugee. The reason for moving was, I was involved in a Islamic group, who teach how to follow Quran in whole other way. Peacefully and only fighting the evil inside us. Our country were against Muslims so the group leader got jailed for being Muslim so some of us fled to other countries. The new group leader, for overseas followers, started to change the rules so I realized this group is not following the way of true Islamic rules, so I left the group. He ordered his followers not to read Quran, because when he came up with new rules, people around him reminded him of what was actually written in Quran, which bothered him. 
My other family members still with the group, so I mostly hear about the new orders. Yesterday, they told me they aren't fasting or praying anymore. Because the group leader said, its not neccessary and told them, if they stop doing these things Allah will open up a new activity, which is more useful to them. 
I was shocked when I heard these. They also said, only people with great Eman (faith) to Allah will understand this rule and follow it. I didn't knew what to say or do. I know I can't change their mind because my family are faithful to that group. 

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
May Allah reward you for the concern you have for your family members who have unfortunately fallen under the influence of this errant Shaykh. We make dua that Allah guide them all to the right path. 
Praying salah and fasting are the commandments of Allah and two of the pillars of Islam. Anyone who says otherwise, no matter how pious or religious he might seem to be, cannot be followed since such a person is following his own desires and aiding Shaytan.
Rasulullah (salallahu alayhi wa sallam) has stated [i]:
“There is no obedience to any creation (which would entail) the disobedience of the Creator”
The statement by your family members that only people with faith [iman] will understand this rule of not praying or fasting is completely incorrect and illogical. If anything, following such a rule will be a cause of depriving them of iman. 
Here are some points that you can, Insha-Allah, present to your family members: 
*The best of creation Rasulullah (salallahu alayhi wa sallam) himself was not exempted from praying or fasting so how could anyone else be? Neither was the best generation, that of the companions (may Allah be pleased with them), exempt from praying or fasting.
*Revelation [wahy] stopped after the passing away of Rasulullah (salallahu alayhi wa sallam) so how can anyone change the commandments that are enshrined in the Quran and the Sunnah? How can anyone overturn the laws that Allah gave to Rasulullah (salallahu alayhi wa sallam) when he (salallahu alayhi wa sallam) is the last messenger and prophet?
*From where does this religious leader get the authority to change the commandments of Allah based on his whims? Who gave him the authority to do so? Can you imagine the chaos and confusion it would cause if another religious leader said there is no need to pay Zakat, and another said there is no need to perform Hajj. 
*In his last days, Rasulullah (salallahu alayhi wa sallam) was ill for 13 days, yet he (salallahu alayhi wa sallam) continued to lead Salah until he became so ill that he kept fainting out of the sheer severity of his illness. Eventually, after multiple attempts to get ready to lead salah and falling unconscious each time he (salallahu alayhi wa sallam) ordered Abu Bakr (may Allah be pleased with him) to lead salah. 
The above episode from the life of Rasulullah (salallahu alayhi wa sallam) shows how much care and concern he (salallahu alayhi wa sallam) had for salah.  When he (salallahu alayhi wa sallam) felt a little better just a few days before his death, he (salallahu alayhi wa sallam) came to the masjid for the afternoon [dhuhr] salah leaning on two companions (may Allah be pleased with them both). [ii] 
*It is also narrated about the great scholar-saint, Shaykh Abdul-Qadir Al-Jilani (may Allah mercy on him) that he once saw a light that illuminated the horizon and a voice called out to him saying that, “O Abdul Qadir, I am your Lord and I have made permissible for you all that is prohibited,” to which Shaykh Abdul-Qadir replied: “I seek refuge in Allah from Shaytan, the accursed. Get lost O accursed one!” and the light became darkness. 
Shaytan called out again to Abdul-Qadir claiming that his knowledge had saved him from Shaytan and that he (Shaytan) had lead seventy people astray this way (by making them believe that all prohibitions had been made permissible for them) to which Shaykh Abdul Qadir replied that it was only by the Grace and Benevolence of Allah that he was saved. When Abdul-Qadir was asked later how he knew Shaytan was addressing him, he said by his statement: “I have made permissible for you all that is prohibited.” [iii]
In conclusion, no matter how much a person excels in piety, the path of tasawwuf, knowledge, etc., he will never be exempted from the commandments of Allah, nor can he change the commandments of Allah. Those that attempt to change the commandments of Allah are serving Shaytan's interests as is demonstrated from Shaykh Abdul-Qadir's encounter.
You should make dua for your family members that Allah guide them to the truth and make them recognize the grave error they are committing. 
Do not despair or give up hope. Try your best to make them understand the importance of salah and fasting and mention to them the points listed above to convince them of the error of their ways. We make dua that Allah make it easy for you. Ameen.
Mufti Sohail ibn Arif,
Assistant Mufti, Darul Iftaa
Chicago, USA
Checked and Approved by,
Mufti Ebrahim Desai.
 
لا طاعة لمخلوق في معصية الخالق [i]
المعجم الكبير. ١٨/ ١٧٠  ٣٨١ 
سيرة رسول أكرم، ٢٨٨ - ٢٩٠ مفتي محمد شفيع [ii]
وصنّف الشّطنوفي المصري في أخبار عبد القادر ومناقبه ثلاث مجلدات، ذكر فيه بإسناده إلى موسى ابن [iii]
 الشيخ عبد القادر قال: سمعت والدي يقول: خرجت في بعض سياحاتي إلى البرّيّة ومكثت أياما لا أجد ماء فاشتد بي العطش، فأظلّتني سحابة ونزل عليّ منها شيء يشبه النّدى فرويت، ثم رأيت نورا أضاء به الأفق، وبدت لي صورة، ونوديت منها يا عبد القادر أنا ربّك وقد حللّت لك المحرمات- أو قال ما حرّمت على غيرك- فقلت: أعوذ بالله من الشيطان الرجيم، اخسأ يا لعين، فإذا ذلك النور ظلام وتلك الصورة دخان، ثم خاطبني وقال: يا عبد القادر نجوت مني بعلمك بحكم ربّك وقوتك في أحوال منازلاتك، ولقد أضللت بهذه الواقعة سبعين من أهل الطريق، فقلت: لربّي الفضل والمنّة. قال: فقيل له: كيف علمت أنه شيطان؟
قال: بقوله: قد حلّلت لك المحرمات
شذرات الذهب في أخبار من ذهب، ٦/ ٣٣٣ - ٣٣٤