Son is overweight and ex-wife doesn't do anything about it and told me not to mention anything about his weight to him.

My son is 15. He's about 5'3 and 160 pounds. He needs to lose about 20 pounds to be a normal BMI range. He gained weight pretty fast. He used to play sports but had to stop due to a medical issues and now plays more video games and has gained a lot of weight.His mom never made the healtiest meals but now that's he's overweight it is becoming an issue. In addition to that he spends many afternoons and Fridays with friends and is usually eating pizza and drinking sodas.I only get him on weekends but encouraged his mom to take him to his doctor. She told me that his doctor said not to diet and told me to not mention his weight around him because it could lead to him try to lose weight in an unhealthy way.This morning I tried to get him to come on a walk with me but said he wanted to stay home instead. I kind of forced it and he didn't mind it that much but he told his mom and now she's mad at me. She told me that he is now talking about his weight and seems more worried even though O didn't mention his weight.What can I do to help my son if my ex-wife isn't on board? via /r/Parenting https://ift.tt/2I4RqKC