<human>: I recently turned 18, and my bil is 30-something. He has been married to my 30-year-old sister for about nine years, and they have four children together. 

A few weeks after my birthday, we celebrated a holiday as a family. Just a simple barbecue while the kids swam. Everyone went outside except for me; I was doing some laundry. Bil comes into the same room as me, looking bored. He tries to start some conversation. His tone seemed lighthearted, as if he were simply starting a casual conversation, but his words were anything but. He just walked into the room, stood around a bit, and then said "man, I wish your sister had boobs like yours!" He quickly realized that he said something wrong and got very nervous, so he followed up with "yeah, she looks better after losing the weight, but she doesn't have boobs anymore." I was speechless, and he quickly walked away.

I told my mom later that day. She seemed surprised, but all she said was "don't tell your sister, she'll get upset." She isn't wrong, but I wish she showed a bit more concern for me. My mother bends over backwards to be the peace-keeper in the family, and she knows that if my sister or dad finds out about this, the family will fight. My sister will take bil's side and get angry at me, and my dad will probably try to kill him.

I just feel so uncomfortable around bil. I always have, even before these comments. I don't want to be around him any longer, but there's not much I can do until I can move out.

Does it seem like the comment I described was sexual in nature? Should I keep quiet like my mother suggested?

Can you provide a brief overview of the text?
<bot>: Brother-in-law made a comment about my breasts. Should I keep it to myself or tell someone, risking causing a divide in the family?