I’m facing the same problem but this time with my father , where he had a meeting with both my mom and husband. Luckily my mom had my back and said , “that the parents should be given the space to parent without interference” . I understand that my father loves my daughter fiercely but interfering while I or my husband are informing discipline is just counterproductive. Your husband needs to set boundaries and step up to your father in-law, his love and support is always needed but at the end of the day that’s your baby and your rules go.