Your second paragraph concerns me. It sounds like perhaps the grandparents or someone there are giving him messages about you that are confusing him. A 10-year-old doesn't ask you to go of medication all on his own. That came from someone and they need to be straightened out. Someone is giving him the message that only crazy people take medications and that medication change who you are in a negative way. It is the adults who are confusing him that need to get in line with the truth and stop confusing your son.