Gosh, that sounds really frustrating and potentially dangerous
.
I can only say what I'd do at this point...so...do you mean he is "deaf" literally, or figuratively, bc I wasn't totally sure....? If he *is* actually deaf, then what I'd do since this man may have limited verbal communication (and may not be able to read lips) is I'd write a kind, factual letter explaining things...and the consequences you're planning if the situation isn't somehow made more safe for the surrounding humans and animals. You could even make it anonymous.
You could mention that if it seems like things aren't improving in the immediate future, you would be very sad to be forced to report the safety issue to authorities....and blah blah. And wish him well and stuff
.
That's what I'd do, for whatever it's worth. I hope it all works it. Very scary to have unprectable creatures in the 'hood...canine or otherwise, eek!