13 Year Old Pomeranian Dog With Repeated Bitting Incident

Hey , i need advice for my 13 year old Pomeranian dog . Since he was young there were multiple incidents of bitting and grabbing multiple people including me , my mom , our maid and a few other family members . Now moving forward today he bite my mom on hand severally and now today he has again bitten her on the leg when she was normally sitting on the bed and he was sleeping under the bed . What should i do? Am really confused and worried about this situation