My brother Tom (34M) recently got engaged to Melissa (32F), who has a 6-year-old son, Dylan (chaged the names). Last weekend, I (29F) was babysitting Dylan while they went out for dinner. Dylan was playing with some toys when he accidentally broke a glass figurine. He immediately started crying and said, "Please don't tell my mom! She'll give me the quiet time!" I asked what "quiet time" meant, and Dylan explained that when he misbehaves, Melissa makes him kneel facing a wall for an hour, sometimes longer if he cries or moves. If he speaks, she adds more time. This shocked me, but I kept calm and told him accidents happen. When Tom and Melissa returned, I told Tom privately what Dylan had shared. Tom defended her, saying I don't understand parenting and that Dylan is "dramatic." He claimed it's just a "time-out" and I'm overreacting. I later confronted Melissa directly, telling her I thought her "quiet time" punishment was excessive and potentially abusive. She completely flipped out, saying I had no right to question her parenting when I don't have kids. She accused me of trying to sabotage their relationship and twisting a child's words. Now my entire family is divided. My parents think I should apologize for "overstepping," while my sister agrees with me that the punishment sounds problematic. Tom is demanding I apologize to Melissa before their wedding. I refuse to apologize for speaking up about something that seems wrong to me. Making a child kneel silently for extended periods doesn't seem like appropriate discipline. But now I'm uninvited from their wedding and causing family drama.

AITA for refusing to let this go and apologize?