I've name changed as this will out me.
My DH has his step brother to visit about 3 or 4 times a year for a long weekend Thursday to Sunday. They've had these weekends since they were in their early twenties and it basically consists of drinking every night and not getting back until 2am or staying up til then talking or whatever. I deal with our three young dc almost entirely alone for this time.
So far so acceptable.
However the step brother is a total nightmare. If he speaks to the children at all it is to deliberately wind them up or make thinly veiled 'funny' rascist sexist comments that he thinks are great jokes as they go over the dcs heads but it's clear they have a double meaning. I always ask after him, his work, partner, hobbies etc but generally get very short answers rather than a discussion and it feels like Im interviewing him. He not only doesnt ever speak to me but won't even look at me either.(?!) He always deliberately leaves an empty packet of cigarettes and other litter in inaccessable but visible places (a shelf in my stairwell, crammed into my lavendar bushes, behind books in my bookshelf to name but a few).
There's also background stuff which I dont feel I can mention even on an anon place but trust me when I know he does some very ethically dubious activities... and attempts to incite my DH to participate too.
I asked my DH why he behaves so horribly to.me.and he said it's because the step brother sees me as getting in the way of his enjoyment.
AIBU to refuse to have him as a house guest again?