You have my sympathies. What a complete and utter arsehole!
First of all, I cannot abide misers and having been caught out a couple of times in the past, I no longer tolerate them.
Last time I unwittingly invited a penny-pinching woman and her family to my home for lunch, she brought a bottle of wine that couldn't have cost more than £1.50. I opened it, took a slurp, winced visibly and said,
"listen, we won't be able to drink this, take it home with you."
She protested that she wouldn't be able to drink it either, and that I should give it to my next lot of guests!!!!!!
Needless to say, we couldn't wait for them to go, and that was the end of that.
As for this sorry fellow you have been putting up with, I would say,
"I'm afraid you've blocked the toilet so you need to go in there and unblock it and leave it as you found it - i.e. clean enough for surgery."
When he's done that, tell him that he is a tight-fisted, ill-mannered person and you can't tolerate him for another moment - he should leave immediately.
There is nothing worse than a miser - if you feel you can get away with it, kick his arse as he leaves through the front door, ensuring he falls to the ground, then slam the door shut.