Hi, really sorry to hear about your Dad
Haven't really played much app poker, except for The Duel that PokerStars released in Beta last year that got discontinued.
Funny thing, was just checking the iTunes store and it looks like PokerStars copied the app from someone else, so the app they copied is still in the store.
Looks like 'Poker God - Heads Up Poker' has gotten lots of 5 star ratings, so maybe that's one that you and your Dad might be able to play?
Hope you're doing well - take care.