tangential: I‘m using a oneplus 6 with postmarketOS but depending on your friend‘s it skills, it might not be ready for him yet.

So far its very usable but I suggest someone must want to swim against the current and do things differently. One could say a „pioneer“ type would be ideal for this.

„Simple“

I agree that being active is important and good for you but depending on the circumstances its everything but simple.

I aspire to move a lot but the day being this active becomes easy will he the day. :)

Technically correct. :)

Kind of how foss in general works as well. If you contribute anything, you‘re technically making the app.

The reasons are plenty, they are laid out here:

https://fedipact.online/why

I‘m not a fan of reinventing the wheel so feel free to ask questions if you like.

If you think you might be on the spectrum feel free to do some tests and/or contact a professional about it.

Its very hard to judge if you are on the spectrum from the circumstances of your birth. Also I didnt catch why it matters. There is no evidence afaik that natural birth/oxygen cut off heightens the likelyhood of being on the spectrum.