I have personally worked with HTC , Samsung and Apple. What I noticed is Apple support , response , eco system , integration,customer approach and how the respond is far better than any other brand. I use pixel and iPhone currently.

After multiple repair if the issue persists, Apple will replace whole unit.

I have used 6 models of Samsung. 4 models of HTC and 3 models of googles Nexus and pixel. One plus.

All I can narrow down is Apple quality and support is much better

Nice of you to get him iPhone. I would recommend iPhone 11. If you have iCloud add him under family sharing so it will be easy to restore and guide him whenever needed

It’s awesome. Only thing I noticed certain app developers are way to slow to optimize the app to read and run all cores so it is heating up. Like Meta apps , certain VR apps.

Again most days I get through the day. But if on constant video calls or voice call for longer period the battery definitely drains faster.

It’s normal. They don’t force fix anything. They have a QC after repair. They had replaced my dad’s iPhone 7 and his 11 as well 😅.