Need some help from yall re: iphone parental locks and STEM projects for kids

Trying to mentor this kid through BBBS but it's been tough. He lives kinda far and with my travel schedule I only get to see him 3-4 times a month.

Standard story, dad not in the picture, etc. I thought it would be tough, and this is what I signed up for, but I also thought I'd have more time to build a relationship with the kid before the situations got more serious, since he only just turned 13. It's only been two months, but his best friend was shot and killed the first week, and he was expelled his from school and suspended from the second, both for weed pens.

Because of this, and because these days, kids have gotten really creative with how to use the internet to talk to each other to buy and sell shite - the mom has basically given up on lettings him have his phone. The kid likes hanging out, and we have fun, but he won't really open up to me about stuff until the end of our sessions, and then I kind of have to start over the next time we hang out. It's been hard without being able to text, and for some reason it's always awkward trying to talk to him on the phone. A lot of one word answers.

He did say he had fun doing some STEM projects in a class he took last year, so I'm trying to encourage that, but I'm trying to figure out the following:

a) Is it possible to set an iphone to where it can only contact a set list of numbers, and do literally nothing else?

b) Do yall have any recommendations for fun STEM projects? I'm looking at Kiwico since that's the only idea I've had so far. He wants to do "cool" projects, but realistically his education level is probably about 2 years less than where it should

Any help would be much appreciated