[Mr.Monkey]

Depending on your father's needs. Since you said he has had a flip phone, I'd recommend you to get him another one. The whole idea of unlocking a phone and pressing a touch screen compared to buttons is something older people will not understand. It is nothing to see my parents who are relatively young fail at the basic function to get to the dailer and dial a phone number with their Android phones than the hardcore monstrosity yellow like piss iDEN i580 my father had for 4+ years before the network was shut down.

If you stand by him and teach him well, the headaches are with you.
But if you do not want to bother with that with your father, then I suggest you to not do it.