My daughter went to high school with Blaze. The high school they attended is a commuter high school in which kids from all over the county or other counties attend. Most of my daughter's high school friends did not know her home address, as they mostly saw each other at school since they lived too far apart to see each other after school or on the weekends. Also, I didn't know some of my daughter's high school friends, and except for one of her friends, I did not have their contact info, and they did not have mine.
Knowing this, it completely makes sense to me that the guy (high school friend from what I have read) who picked Blaze up did not know his home address. It also makes sense to me that the parents did not know who this guy was or had any contact info for him.
Personally, I think this guy did what Blaze asked him to do which was drop him off at this park, and after Blaze disappeared and did not most likely respond to this guy's texts, he became worried and eventually returned to the park at 4am to see if he could find Blaze. My theory is that Blaze is a victim of a Grindr hook up gone bad with whomever he was meeting at this park.