Breastfeeding in front of men/family

So my friend is big on breastfeeding, she doesn’t carry any bottles with her, she feeds on demand.

She comes over frequently and my sister in law was giving her son a haircut yesterday and he was crying so she she started feeding him.

My brother in law was talking to her before she started feeding, went to wash a dish and came back to her breastfeeding and he looked at her then turned around and said nothing about it.

Well today he very randomly brings it up and is so against it, says it’s disrespectful but he’s not 100% with b-feeding but she should have let him know before she did it so he knew it was gonna happen.

I said no, you have the choice to look at it or not, her nipple isn’t shown and all she’s doing is feeding her baby.

He compares it to...🤦🏽‍♀️🤦🏽‍♀️🤦🏽‍♀️ “it’s like me pulling my dick out to pee in front of everyone”.

I cant get through to him. He told me “ I’m just gonna stop, cause you’re gonna lose” and he even asked his wife if she was uncomfortable and she said yes. So its like.. how old are we? We all have nipples so if you happen to see it, it’s not like she has something no one else has. But I have been around her multiple times while she feeds and have never seen her full nipple

I’m just so irritated with him.

What are your guys thoughts on breastfeeding in front of men or family? Due to corona I was in my room almost all day so its not like I was ever around anyone for them to see my boob out or else I would have tried openly feeding.