Before this all happened, he was forgetting passwords, had trouble logging his Nook onto his wifi, and had other problems with tech. Now the confusion is more generalized, but now that he is out of the hospital, and in a stable environment, my mom and I think that having a computer will help keep his mind sharp, keep him connected with family all over, and entertain him.
I live 1000 miles away, but can still help advise for a computer. We were thinking a thumb scan or something similar for logging on, and something to track it in case he has to worry about losing it or it 'growing legs'. He won't be doing any banking any more on something like that, but simple security would be nice — the place has a network.
I also suggested that she get it set up (all I know of is the Geek Squad if she goes to Best Buy, otherwise she can look locally for someone) so that she is the administrator, so if he gets a ton of spyware on it (again, another sign of his faltering abilities) she can get it cleaned up by a closer, semi tech literate relative near her.
Any suggestions? He never used Macs, he used Linux only sporadically, but used Windows frequently at home. It would probably best for him to continue with Windows.