Are there any federal grants avalible to repair my dads home he is 74 yrs old and has no money what can I do

There are Reverse mortgages... but they aren't free... also you could also pay for them.

There are no federal programs, and nothing that the taxpayer (he, you, and I) pays for, which is all government money, is free. Everybody is paying for it.

Some towns have programs to assist with home repairs for seniors (with no one younger living there) but most of those have dried up during all the lean years.

If you are able bodied, you should be working on his house. If your father raised you under his roof, and fed and clothed you, it should be an honor to return the favor. If the repairs are beyond your ability, ask him if he will sell the house and move in with you. He'd probably be glad to give you room and board, a good deal for all, and the way it worked for hundreds of years.