I don't frequently get upsell attempts by my audiologists, but they will lay out some options. They'll say "This one is what you need. If you want Bluetooth, this one works better for most people. This one over here has a really great iPhone app but doesn't work well with Android." I never have had someone say "You absolutely must use this one, because I said so."
TL;DR: Take your dad to an audiologist, get a professional opinion, get a second opinion if you want to. I would recommend getting your hearing aids from an audiologist and not a "Hearing Aid Center."
Good luck to your father! Hearing loss is tough, but treatable!