Blimey!
First off, KK, can I just congratulate you on being an amazing woman. Seriously. Not only do you have an immense capacity for love, you're also the competent, capable businesswoman-cum-mother who has, essentially, been a single parent all these years while still handing out the love. As if that's not already more than enough, your innate intelligence alerted you to the fact that stuff was going badly wrong and you sat down and addressed it. Don't ever underestimate the brilliance of what you're doing here.
I expected this to happen, but not so suddenly. Even in mid-meltdown, he still managed to reject all responsibility (It's the non-paying tenant's fault? Er, no, it's the fault of the man who built a precarious empire that never pays out.) The threats to beat up said tenant, go to prison, live in a field and hurt you seem, unfortunately, to be expressions of his world: one where he is either king or pauper, with no responsibility either way; where anyone and everyone else is to blame and he claims the right to punish them. Bit of a blow for you.
I shan't add to your sensible replies, especially as your head's getting more screwed on by the hour! I'll repeat the warnings, though, that after the storm will probably come a full-scale charm attempt followed by determined manipulation.
Who can you call on for moral and practical support? Call them.
Keep going ... You so are going to be all right, however this shakes out :)