Am I the only one??

My brothers child always touches my son. He will try kissing him and shaking. He doesn’t listen. They also don’t believe in the word no so they will direct him to another activity if he is doing something wrong? I can’t stand it and now that it’s flu season. I just think it’s best if he stays away because it’s not work my son getting sick. I also found out that they don’t do the flu shot which I know it’s not a 100 percent but my son isn’t even 4 months yet and I don’t want to risk him getting sick. So they are beyond mad and said that it’s not a big deal if their son misses the baby. That the baby will be fine. I can’t argue anymore. Idc what anyone believes as a mom if I make rules then just respect them please and thanks