A house for my dad after covid

My father is a vietnam veteran and was recovering his mobility in a VA home from a surgery on his back due to agent orange. He contracted Covid-19 in the VA home and has fought for his life during 2 hospitalizations. He will have permanent lung damage due to the virus Covid-19  and will likely be on oxygen for the rest of his life. He is now back at the VA home to regain his strength and mobility. When he has completed his physical therapy there, we would love to be able to put a down payment on an accessible house for him so we can live together as a family for the rest of his days. Thank you for your help and support!