I would encourage him to eat less meat gradually vs deciding to just go full vegan all of the sudden. It doesn’t have to be all or nothing. He may find that eating meat once/day or 2-3 meals per week is a good balance. If he wants to be vegan for ethical reasons, less meat is still going to help the planet. If he’s doing it for health reasons I don’t think vegan is any healthier than meat-lite or vegetarian. Stay away from the super processed vegan alternatives, though. The fake “cheese” and “meat” are worse than just eating the real thing.

Veganism doesn’t look healthy at all.

Who wants to eat plants and beans all the time? Dairy and meat are nutrient rich food groups for a reason (calcium, B12, iron, magnesium, vitamin D): Nothing is as nutrient dense as beef, salmon, chicken, cheese, milk, or eggs .

A balanced diet is far healthier overall than a vegan diet

My kids are not 3 and 4. All three are teenagers.