from grandma to mom

I was adopted my my grandmother when I was two. As someone who has actually lived through the situation, not a therapist, i STRONGLY recommend you encourage him NOT to call you mom, especially is he is still going to have contact with his biomom. People, his peers, will already treat him differently because he does not live with his parents, calling you mom will only make it worse. There will come a time when people will ask questions.. my mom is really my grandma is a difficult family dynamic to explain for a child growing up. Eventually he might be confused about how he feels, resentful, embarrassed..I'm not sure if those are even the right words, its difficult to explain how I felt about it, how I still feel about it, and its still frustrating to have to explain my family to people or having to say mom vs biomom when referring to one or the other. My husband even gets confused. All i know is things would have been infinitely easier for me if i could have just called everyone what they were..mom grandma, dad, grandad, aunt, brother ect. none of this mom/grandma, sister/aunt mom/biomom stuff.