NC for identifying details :)
My xMIL is a sweet, although tricky and complicated, woman who loves DS (4) more than anything in the world. DS adores her too and I am extremely grateful for the lovely relationship they have. She lives in Ireland, but visits several times a year. She would never hurt DS intentionally, but she is really very scatty, doesn't always concentrate and can be irresponsible. For those reason, XH and myself would never leave her to babysit DS for extended periods or overnight. I am actually slightly less vehement on that point than XH, but there is one thing I am absolutely adamant about - DS is never ever, ever allowed to be driven my her and I mean that. When we were still married, we drove over to Ireland to see her and XH made sure he always drove and somehow we've got to 4 years without actually telling her that neither of us want her to be at the wheel if DS is in the car.
She has a conviction for dangerous driving - overtaking on blind rise at 70mph causing a head-on collision which miraculously didn't kill anyone. She didn't lose her license at the time because she'd have lost her job, but got 11 (I think) points. She once drove XH and I to the airport (pre-DS) and I was genuinely scared for my life the whole way. I have never been so grateful to get out of a car and when we landed back in the UK, we got a call to say she'd had an accident and written the car off on the way back.
DS spends a lot of time with my mum and step-dad - at least 2 or 3 weekends a month and has had a week's holiday with them. XH is very happy with this, although we try keep it quiet from his mum obviously that he was on holiday with them. There are two of them vs one of her, my mum is 10 years younger and we're very happy with him being in a car with them. Anyway, my mum and step-dad very dearly wanted to take DS to Italy with them this summer where step-dad's daughter lives. XH said 'No' to the idea because he felt that DS was too young to leave the country without either one of us. My mum was very disappointed, but accepted she needed both our permission and that was that.
Last night, XH tells me that his mum is insisting (his words) that he visit in the summer for a long weekend with DS and she'll be paying for the flights. So far, fine, but XH says he can't afford to hire a car for the weekend so it'll be unavoidable that xMIL drives them to/from airport (over an hour) and they'll do loads of driving (visiting relatives) every day on country and steep windy roads over hills. I am really unhappy about this and so is XH but he is very reluctant to say anything to her. She will be very excited, quite manic in fact, and probably won't have slept when she would be collecting them and basically the idea sends shivers down my spine. My mum has offered to pay for the car hire, but I think that would be a bit strange?
I guess I could probably put my foot down over this (not sure if I could legally stop him taking him to Ireland) so ideally XH finds a way to get a hire car, although FIL has told us numerous horror stories about the hire cars not being safe so XH is pointing that out. It'd be really expensive (he has a thirsty big car) and take too long for him to drive over there.
How would you handle this?