<human>: Some background on our relationship: My brother was always hesitant about his sexual orientation and discussing it with me. He didn't want to come out to me either but his friends persuaded him into doing so (this was about 5 years ago) Our parents are pretty conservative and have no idea my brother is gay and so does most of our family and friends.

Okay, so... here's what happened. I only wanted to check my email on our family's computer (we still live together) and I found that my brother was still logged in. I noticed a string of Craigslist emails regarding meeting up with individuals (who were way older than my brother, around mid-thirties) for casual sex. Now, I know it was a major invasion of privacy but when I see an email that they want to meet up at strange times in the night, I'm obviously going to be a bit concerned. 

Well, I confronted my younger brother about this. I told him I was concerned and worried. I told him to stop doing it because it didn't seem safe. He told me that he's going to keep doing it and that he's sorry that I found out. He also kept telling me that he still doesn't feel comfortable with me knowing about his sexual orientation. Then he listed people who he trusts more than me. I was a little hurt because he just went on and on about how he doesn't trust me. I've always considered him as one of the closest people to me. Now he's ignoring me because he doesn't like how I'm trying to "control him". He doesn't want me lecturing him like an adult.

Condense the text into a few key points
<bot>: My gay younger brother is having sex with older strangers he meets through Craigslist. How do I handle this situation as the concerned older brother?