I've namechanged, though I realise if sibling sees this the shit will hit the fan anyway.
I have a sibling, I'll call them X/they. Until recently sibling was my sister but has "come out as non-binary". They also have multiple other diagnoses, some self-diagnosed, some not, including ASD (also recent) and was previously gay. This is relevant. I have tried to be supportive but I also feel that X "collects" diagnoses and has a huge agenda to seek an identity and be a member of special needs groups, if that makes sense. They are surrounded by other similar people who all talk a lot about their gender/SN issues on twitter and are very vocal and demanding. I don't want to sound bitchy, just trying to describe the situation. But full disclosure I am gender-critical and what X would call a TERF, but I've just avoided discussing this.
Thought my whole extended family is a dysfunctional wreck, I have mainly got on with X well, though not been super-close. X likes to visit my town for a particular event each year, and has stayed with us in the past, sometimes with spouse from whom X is now separated. They have been disorganised and messy, but not to a terrible extent.
This year I was away on holiday during said event and I asked X if they would like to stay at ours and cat-sit, they agreed. I paid towards transport as a thank you (X has v little money).
While we were away I had texts from X complaining that cat was being sick a lot, she is a sicky cat at times so I apologised but didn't think much of it.
We got back shortly after X left and were horrified to find an utter bombsite. Spilt used cat litter all along the hall, and also trailed outside, which I had to deal with immediately to avoid upsetting neighbours. Whole toilet and seat splattered with dried-on poo. Kitchen splatted with every kind of food mess. Bed X had used was full of old used plates, spilt food, tampons, suppositories, sharp cutlery and random items. Worst of all, the cat's dishes were encrusted with several days of food and it was very hot weather. She'd been eating from increasingly dirty dishes and X hadn't been cleaning/replacing them, so no wonder she was ill. Poor thing was traumatised.
I was very, very upset, especially as we'd just had an exhausting long journey (just me and kids, I'm a single mum) and I had to clean everything up. The kids were furious about the cat and said X could never stay again. X never mentioned anything, explained or apologised so it's not as if there was some particular explanation.
Well you know where this is heading. I was going to talk to X about it and chickened out and never did it. Now X wants to come and stay again, and I don't know what to do, how to approach it and what to say.
The problem is that X is very sensitive and has a victim-like mentality, and often uses their diagnoses to explain that they aren't capable of various things. But in fact they used to be able to cope, before all these diagnoses, and were never this bad - messy yes, but able to do basic housekeeping and have never left a toilet like that before.
I have always been like the "grown-up" among my siblings and feel like they act more like children around me, which I hate. If I address this I will be the oh-so-perfect big sister "telling X off" and it will just reinforce the dynamic even more. I also don't want to fall out with X at this time. Though I'm not an expert, I've had my own MH issues and I suspect X is depressed and doesn't need to be abandoned.
But my kids matter too. I could cope with X staying briefly if I was there, but they don't want X here at all.
I need to reply to X's email asking to stay, what would you say? (Btw email is by far the best way for us to talk, it won't be by phone as we both dislike it.)