I don't think the features you mentioned (water resistance or telephoto lens) would matter even the slightest for your dad. I mean he is still still using a Realme 3 Pro for God's sake. You need to be realistic and observe (or even ask) what your dad needs the most.
Elderly parents wants functionality and convenience more than performance or gimmicky features. For instance, none of the models you mentioned come with a headphone jack, and for a elderly person (can relate to my dad), it is a must have feature because using wireless headphones or dongles can become cumbersome. Having an option is always a plus.
Similarly, you need to look at models that are lightweight, has a bright display, and have a very good battery life, because for them having a heavy paperweight or something that needs multiple cycles of charging will be an inconvenience.
I'd suggest looking at the Poco X6. It is a lightweight all-round device that comes with stellar performance for the price (7S Gen 2), pretty good camera, has a headphone jack, very good battery life, bright display, and fast charging. Seems like a no-brainer to me.