My 10 year older brother in law 
commented on my photo via private message on Instagram, I didn’t feel I did something wrong but when reading the messages I can’t help but feel a bit guilty. I showed to my husband who said this is strike 1 so he will see how it develops but he is more worried if my sister gets to see this that she will simply quit my brother in law. What shall I
What’s wrong with your sister quitting that loser? If you love your sister be honest about it and tell her. Imagine if he is doing it to you, what he does to others who have 0 conection to your sister… Just make sure you tell her in person and explain the situation completely so he does not get to spin the story against you.