My brother in law is obsessed with me

You are the " Big Dog " here , you just don't know it yet.

Bad Boy is correct. It is 100% up to you to stop any contact with your bil. Be careful of Stockholm Syndrome, because people like your bil are really good at the whole game of being a predator, and they are masters at knowing just the kind of person to victimize.

I would just stay away from that brother in law as best I could. You are of an age where that should be easy enough. My brother-in-law was mean (to everyone) and never had a nice thing to say. We were all rather "happy" at his funeral, he was not particularly missed. There was a friend of my stepmother's (a woman) who had a weird attitude about my niece (my stepsister's youngest daughter) and was always putting her down even when she wasn't doing anything at all -- good, bad, or indifferent! We sort of joked about it (probably not a good response) but it was sad when the woman died and left my stepsister, myself and oldest niece money (all women - to get the money we had to sign a statement we would not allow any men to tell us what to do with/control it) and nothing to this one niece. My stepsister's 2nd husband was offended saying, "She doesn't even know me!" :-) People are/can get weird! That they are related to one doesn't matter.

You know what you know and what you like and who you want to be around, etc. I say go with that on this one and try to avoid him or make sure you are with the whole family/not "alone" with him.