Young Athletes and Supplementation

My young brother of 13 years of age is showing a lot of promise in both long jump and 100m and I’m looking to help him out over the summer with regards to his training and eating.

So I was thinking about supplements to help him with his performance in these events:

Alpha-GPC
Creatine monohydrate
Beta-7

Would there be any issue with a young lad of 13 years having these products?