By transferring his property your grandfather has shown that he trusted his son to look after his needs and that issue must be emphasised to your uncle now.
As far as Shari'a goes, any estate he has (if at all) can only be distributed after his passing.
If there is no one to look after you grandfather, then despite your difficult financial circumstances, it becomes the duty of your father to arrange for accommodation.
Your grandfather can claim back his pension at least, which should help Inshallah.
I think it may be beneficial to seek the help of local community elders to intervene and come up with an equitable solution.