IMO, he's either a pimp, drug dealer, or both. He could just be a pimp (since he was not arrested after a search of his car/apt., therefore possibly no drug paraphernalia) and Hannah COULD have contacted him via social media/CL/got his name from someone for drugs, and his real intent was something other than that. I lean toward her not knowing him at all and he just being a very friendly face and made her feel safe with his psychotic ways . I think the woman he "high fived" was giving him money for a trick she just turned.
All my opinion.
I hate to say it but I was the one who initiated the drug discussion and was completely shot down, but I always trust my gut and my gut told me drugs. Pimps and drug dealers are often one in the same AFAIK.
I grew up in the mean streets. I worked in a crisis center. I just feel like I know the signs better than someone who did not live in the middle of these types of people. Sorry to offend but if it walks like a duck....