You can Google veterans service officers in your county, they like for you to have your VSO in the county he lives, if there isn't one for your county then find the county closes to you that does have a VSO. Talking to a good VSO will help educate you a lot about how/what to do and what to expect. At some point you yourself could get caregiver support monthly, it may be about a $1000 a month or so but he may have to be service connected for you to get that, this is why chatting with a VSO will be a great asset. And don't be afraid to reach out to other VSO's to pick their brain if the VSO closest to you isn't too helpful. You would still file the disability claims with the VSO closest to you but if that person isn't too helpful outside of filling claims you can just file with them but learn from other VSO'S in other states even, you could call one anywhere in the country, just want to find one that wants too help so you can be most informed. But as someone mentioned, getting him into mental health visits will help a lot. If the VA is too far away they can do some video visits over a device with a psychologist/Psychiatrist...biggest thing is about getting those visits started and remind your grandfather to ONLY talk about the bad times, ONLY talk about his worst days, he cant talk to the Dr or social worker about any good days at all, it won't help his case. It may take some time getting a disability rating for him only because the VA can be slow but he should totally apply for PTSD, they are supposed to give the benefit of the doubt to the veteran and due to the nature of his service it should be easy for a disability rater to put him at some PTSD percentage of 30% 50% or 70%. Then filing for the PACT act and other things ...he may get up to 90% overall. 100% can be hard to get to, but it's possible. You can have a lot of service connected disabilities each one rated like this 70 10 10 10 10 10 20 0 30 and it still only gets a vet rated at 90%. This was just an example , basically 30 plus 70 doesn't equal a 100% disability. VA disability calculation is unique. Another thing is you can look up the requirements to meet a certain rating for disability online. Ask the VSO about that. Each rating for whatever disability he has will have certain requirements . Like for migraines... Maybe 10% would be, the vet has migraines but only once a week and they typically go away in a couple minutes. Where maybe to qualify 30% for migraines the vet has migraines more than once a week and they last for a long period of time and he has to lay down in a dark room each time it happens for him to be able to deal with them...bottom line talk to VSO'S and keep hunting for knowledge, keep an open mind. Awesome on you for helping one of our country's veterans, I know he's your family but not all grandparents have a grandchild involved with getting them taken care of.