Do you have see any common thread among people who (until the situation is revealed) seem to have a trusting relationship between parties? I'm just curious because I observed a similar situation with in-laws where the child was misusing their POA/access to funds for an aging widower'd parent. It' been resolved now (well the money is gone, but they've protected what's left and have someone else managing his money), but I've always been curious as to what the mindset was. Do they typically think that somehow/someway, the hole will start getting filled instead of getting deeper?
But I totally get how it took him awhile to realize and unravel what was actually going on -- even when you observe things that don't make sense, it takes awhile to acknowledge/accept that people you know/love had the nerve to actually be this stupid/selfish....because you just can't even fathom it.