Sometimes, the simplest answer to the question is the right answer to the question.
The shame of it all is that quite a few people saw him before he found the dumpster and yet nobody helped him.
Yes, I agree with that being a good possibility. And if that was what happened, it meant that the mugging occurred between the train station and his actual parking garage. That makes sense.
Now, how did he get home to New Castle then (to where he talked with the pharmacist while his car was still in Wilmington)? What's with the noise over Christmas?
Then how did he get back to Wilmington for the parking garage incident?
Then where was he that night?
And where was he all day until 8:30 pm at Nemours building?
And how did he get from Nemours to Newark dumpster in the next 8 hours?
There are other people who know things--who gave him rides, etc. And these are only a few questions. The reported boot footprint in the kitchen, etc...they can be red herrings or important.
Note that people did try to help him. He refused help, and though disoriented, his responses were reportedly labored but lucid. In fact, people might have given him rides, not even now realizing this is in the news. Plus, if every disoriented person in Wilmington had a police report, we'd have police doing nothing else!