From what you explained he lives in a 600K home that at one time had a value he perceived as $1.1M. My guess is he’ll be fine if he wants to stay there. As you said he had some equity from his previous property so lets say he owes about %500K in which case he’s got plenty of equity and should be able to withstand anything but a crash of more than 50%.
I dont see the problem here? I know of retired blue collar workers on the east coast living in multi million dollar properties they bought years ago. It’s not only in CA. People have built wealth in RE for all of time that they could not build any way else. The fact that he is a health care technician is meaningless.