There are a lot of good bows out there for not a ton of money. Most bow companies have a cheaper line nowadays. Hoyt has Reflex, Mathews has Mission, And Bowtech has Diamond. Plus there are many more that are not high dollar bows. Have your dad shoot some of these at an Archery shop to see what suits his style. If his is an older bow, just shooting one of the newer models should get him back inthe game.
Or once he figures out what he wants, he could probably find a used one pretty cheap. Check out the Archery Classified Forum here. Lots of bows for sale there right now with everyone picking up new ones.
Good luck getting your dad back into archery.