Was browsing online to see if anything random came up about Brian and found this page. Figured since you all were spending time and effort in trying to sort things out I would help try to clarify. I'm a friend of Brian's, went to school together, rode bikes together, etc etc. I, along with my friend Niko, were part of the initial group of people searching in AZ for Brian right before his dad got out there. We left on Memorial day after 3 complete days of searching/flyering.
Some tidbits:
Brian was not heading to South Mountain to ride his bike, he doesn't ride bmx trails really, and it would be nearly impossible to ride the majority of South Mountain trails on a bmx bike. The location that his car (with bike & wallet inside) was parked is low key, serene. It was across from a vacant home or two, he wasn't in them, we checked. The neighbors in that location saw Brian, they saw him come to his car and leave (and come back again, as I recall). Some of the neighbors seemed shady, however there was supposedly a report of a rancher that Brian spoke to a week after he was missing a couple blocks away from the initial location, Brian's dad confirmed this report since the rancher had info that no one else had about Brian (i'm guessing his clothing) but everyone seems to now say he wasn't seen after his initial disappearance which I believe makes things sound more bleak. He was spotted naked praying in the field next to his car, that was the second time he was spotted naked that day, someone else talked to him earlier on in a different location and told him he needed to get his clothes back on.
My friend & I flyered from Guadalupe West across the neighborhoods that were adjacent to the South Mountain park to the point where Brian's car was found as well as the bus stops that runs east/west.
Brian's gf left AZ a couple weeks ahead of his disappearance. Brian was in Philly a week or so before his disappearance for a wedding I believe, I've heard that his father had an argument with him. I don't think either of those items are really a direct factor in the whole thing but perhaps relevant to the background of his state of mind.
Brian has hit his head before, lots of hard landings and slams, but that's fairly common with bmx especially at the level Brian rode. From what I was told, from the people who rode with him that week, he didn't have a hard crash lately. Most of the bmx riders that are friends with Brian aren't too sure about the theory of him having trauma to the point of being out of it.
Brian is very focused, on what he wants to focus. That could be a new clothing company, that could be filming for professional level bmx video edits and I kind of think that could also his new found interest in religion and maybe even a long trip? He recently had found christianity, which if you knew Brian was a big surprise for me to hear.
Brian is a people person. He has a great ability to interact with just about anyone, he's the type of person you would want to help. From the descriptions that the Co-op grill left about the person they think was Brian that stopped by occasionally, it sounds like a distinct possibility (I would follow up with them to verify their sighting).
Brian is very minimalistic. He prefers setuping up a tent instead of paying to stay someplace, doesn't mind eating some free samples and just going with the flow of things. Not having his wallet wouldn't ruin his day, and if you offered he might not turn down a free meal.
Brian said about being at Bam Margera's house (skatepark) before as they have some mutual friends. I think its in the Orchid Footwork dvd, but Brian doesn't have any clips from that day. I don't see Bam helping in this but since there is no search effort, I guess it could be worth a shot.
One last tidbit, as if you weren't tired of reading this haha. My wife and I have been discussing the whole thing for over a year now. Our theories have changed over the course of that year, and one interesting thing we've noticed is that when a sighting pops up and people flock to that area, it seem he never shows up again. The fruitless organized searches, sightings at the grocery market, the Co-op grill sightings were he supposedly showed up on Sundays at about a 2 week interval?, etc. once it was posted on Facebook, he didn't show up again.
Hopefully brian is off on some great journey of reflection and spreading the positive vibes he is known for.