I’m trying to remember a movie from the 90s and a man that was given away or given up for adoption or something. The guy had a bad life or something and was crazy. He finds his mother and finds out shes remarried and has another son and husband. He believe he starts working with the new husband and gets close to the family. Eventually he tells the mom who he is and then he goes crazy and terrorizes the family. He rapes the new son, i think he kills the husband.