Hi Mike, nice to see you're looking after your son.
To tell the truth, it took a while for me to get used to the taste of soya milk, but it grows on you. I think it best to have with cereal first, rather than a big glass on its own.
The different makes vary considerably in their taste, and don't give up if you find one of them disgusting!
I would recommend a fortified one with B12 and maybe calcium and definitely sweetened with apple juice for a 'beginner'
Alpro 'blue' cartons are a good choice.
Rice and oat milks are quite nice and may be flavoured with vanilla, but they contain less protein for a growing(?) or sporty lad.
Just spend a few quid experimenting, because everyone's palette is different of course.
You never know, you might make the switch to a healthier drink yourself, and in the process, reduce the amount of methane (23x worse than CO2) being released into the atmosphere by dairy/meat farming!
(Alpro soya does not
come from cleared rainforests).
You don't have to declare yourself a veggie to reduce your carbon footprint and animal suffering! I know loads of omnivorous people who are starting to drink soya milk as a healthy lifestyle choice. Convert the whole family!
Live and let live.