Question Summary:
they told me its n’t allowed to pray or make (dua) for him and to pray by his jenaza (dead body) so just want to know is it allowed to make dua for him or not and is it allowed to make haj by his name for him pls advice

Question Detail:

 my dad before he passed away he was very sick and he isn't pray so after he will passed i will make dua for him but some of them they told me its n't allowed to pray or make (dua) for him and to pray by his jenaza (dead body) so just  want to know is it allowed to make dua for him or not and is it allowed to make haj by his name for him pls advice

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatoh
If your father was a non-Muslim, you are not allowed to make duaa for him. However, if he was a Muslim (and it seems as though he was) it is permissible, in fact it is good to make duaa for him.
Yes, it is also permissible to perform Haje-Badal on his behalf or even a nafl haj on his behalf. You perform haj and transfer the thawaab over to him.
And Allah knows best
Wassalam
Mufti Ebrahim Desai
Darul Iftaa, Madrassah In'aamiyyah