I'd say that good intentions don't always result in good or happy endings. Y? Well for some recipients feel they become entitled. Not all but some. Seems those 'some' end up in front of the nicest folks.
B, you are one of those 'nice folks' and your former tenant seems to have hooked with one of those not so nice folks. He influenced your tenant that caused you undue pressure a period of time. Is it a big deal? Well if you think about how much this has raised concerns by folks who care about you and yourself, it is big enough of a big deal. Don't let anyone tell you anything less.
So B, give yourself a rest from borders. Relax in your own home.
You certainly deserve it and for what it's worth, some of us will rest easier as well.