Tablet or iPad recommendation for "older" parent

Let me preface buy saying my dad is 89 years old, and is very literate when it comes to computer use. He has been using an old iPad of mine and it has seen better days. His laptop is also on it's last leg. He is in need of an upgrade and has asked me what he should get next. He is leaning towards the tablet use, but will also need a keyboard for his online trading , email and overall ease of use. The only apple product in his home is the iPad.

We recently upgraded him to a Samsung smart TV and he also uses a Samsung phone. One of his requests is that he wishes to view pictures on his devices and be able to stream via his tablet to the TV. Besides going the appleTV route synced with an iPad, what do the tech gurus of the OT recommend for tablet use (non apple) that could sync with his TV.

I have tried to keep him up with the latest technology, and he is pretty good with it.
Cost is not prohibitive, but would like to get him the most bang for his buck

Thanks!