I'd also suggest the family (over the PI) getting in contact w/ someone from the SDPD HOT team (homeless outreach team) as they are a tremendous resource and specialize in dealing w/ the homeless/transient community.
A little about the HOT team
https://www.sandiego.gov/homeless-services/programs/hot
Public line for the SDPD HOT team: (858) 490-3850 or (866) 737-3468
And hopefully just as a bit of possible encouragement, I'm continually impressed w/ how well, on the whole, SDPD does in knowing so many of our citizens, across the socioeconomic spectrum.
It's amazing how often a call to an address has someone recalling a previous interaction or just having met the resident there for one reason or another (anything from, I believe there was a recent death in the family, to knowing they had someone with special needs of some sort or a physical need, to of course those who they might have chronic interactions with for some reason or another)
Many know the local transients who tend to live in or frequent their beats, personally, and at least portions of their stories, and know who the most well connected of the transients tend to be and/or who typically stays where and with whom, etc.
Because of increasing violence, it's far less common, even just over the last 6 months, for anyone on the streets to really stay 'alone.' And many of the few who used to are increasingly staying in groups or at least much nearer others, which also ups the odds that if Lance is out there in the area, someone's had contact with him and it's just a matter of finding that person / those people.
But in general LE awareness is enough that even w/in the transient population where people might move around every few months, someone will call in a welfare check on someone who they might think is acting unusually, and you'll hear an officer say, "Oh that's ____. I know him/her, and he/she just _____ (dances) to _____ (stay warm, stay upbeat). They're almost certainly Code 4, but I'll go out and check" or something along those lines. Or "I had contact w/ ____ yesterday because someone was concerned the child w/ her wasn't dressed warmly enough, etc. They're going to be ok and stay ____, but I'll go check in to be sure" type of thing. Sometimes you'll even hear someone who lives in the area only a few months a year suddenly appear back in town and officer know just from the call description who it likely is and some general details!
So it's unfortunate that's not the perception the family has gotten.
Also, if he did actually connect to dispatch on any of his 911 calls, if they had the time of that call from phone records, someone here w/ a subscription for Radio Reference, etc. may be able to pull the dispatch log from the scanner files (wouldn't be able to be posted/discussed up here but could be 'downstairs').
If it were a matter of someone disoriented or possibly confused as it sounds like may have been the case with Lance, and he were able to stay on the line long enough or gave an indication of that disorientation/confusion/need or something along those lines over the call, they'd almost certainly have tried to triangulate or ping his phone to get within a certain radius to so they could go try to check on him more specifically.
That happens dozens of times an hour most nights, actually (for various reasons)
It can't always be done, and unfortunately often they still can't find anyone because they stay on the move (though if it's something that they got enough to feel was pressing - as if it were hours ABLE as up and flying - they'd possibly even have had ABLE do a flyover to FLIR the area and search...though it depends on weather as well as the time of night...and we had had a lot of fog grounding or limiting ABLE back in late October / early November)
Obviously if he never connected or they were all hang-ups that's not the case, but if he actually was in communication, assuming he relayed some information so they knew there was actual help possibly needed, it's definitely possible that happened (which you'd hear being dispatched if it came in over 911)
However if he left the area and wasn't as close to the hospitals and/or didn't give his name, it'd take more listening in order to check back in a broader area that far back.
If it would have come in and/or been dispatched solely as medical, it'd be a little harder, and perhaps less of the above happening, but given it'd probably have been considered a 10-8 (person down) type of call, it'd probably have routed through PD and not just fire (which would probably prove helpful in some ways in this instance).
So it's worth trying to check phone records to see call length to determine the true possibility that he actually had voice contact w/ someone.
And just so people know, even a 911 hang-up call from a pay phone gets dispatched and the area checked if no one is found (sometimes dozens an hour) so even if he also tried from a pay phone whether he made voice contact that way or not it'd also have been dispatched and checked.