If only I could remember 1/2 of the truely foolish things I said when my kids were new-born! Being a parent is the biggest, longest learning experience any human can undertake - If you choose to learn from it. New moms are extremely protective ( psycopathically so - think mother bear with cubs). By the time the child is two and mom is tired of the noise, she will be looking for someone / anyone to take the kid somewhere / anywhere that she can't hear the screams so she can get 1/2 hour of sleep (which she won't have had for roughly 2 years at that point). Somewhere around 4 years into it there will be some return to sanity and at that point male figures may safely get within 100 feet of the child with out being savagely attacked. Around 6 years males may be allowed an opinion on the care and education of the child. By 13 neither parent nor child want much of anything to do with each other but that is when ( in the case of daughters) the fathers become psychopathically protective.

It's all good! Keep a sense of humor and stay friends with your sister. Whatever she says now will change when the hormones settle down - sometime around 6 months after weening. Don't rush it.