Rely on your mother instincts and don't let others' opinions bother you. When we think of all the animals that suffered and all the toxins we fed her, we feel awful. We think it is great that you are going to raise your son vegan. Kids who eat meat have problems too. It seems people evolved to be able to eat flesh for survival but if people only ate flesh they would have a lot of problems.
People can be more than healthy on a plant food diet.
I was pleasantly surprised to find my health improve on a vegan diet. In particular, my circulation improved. I don't get out of breath as I once did. I attribute this to cutting out all fats that are solid at room temperature. My husband noticed the same thing.