I am so sorry and don't know what to say. What a terrible situation!! My best advice right now is to read the book "My Child Won't Eat!" and read it cover to cover (it's very short). Gpa is sadly mistaken on his parenting advice and he is hurting your DS as well as your confidence in yourself as a mother and therefore your relationship with DS. Solids and formula are not going to fatten him up better than BFing, and if he won't eat it's because he's not hungry (as you've said). Children grow at their own pace and forcing them to eat will only cause problems down the road, as well as making everyone's lives miserable in the short term. Good luck to you!!!