This isn't a case of financial abuse. You've admitted you're no good with money and have been in debt as a result of spending. You're also happy for him to continue managing the finances.
You also said you didn't or don't want to go on holiday to the place he's going and that's why he's going with a friend. You were given the option to go first.
It may well be that having committed to that holiday, there isn't enough left for a big family holiday this year.
I must say thought, I don't see how far you can get on £1000.00 for a family of 4. That's not enough for flights and accommodation, especially if you're going during school holidays.
I also don't like him waiting for your inheritance to buy a car. I would really object to my DH making plans for himself with my inheritance, because I'd never do that with his. I don't think I have the right to do that.
I'd go as far as getting my parents to specify in their will that money was just for me, if I detected his plans for it actually.
If I leave an inheritance to my DC, it's not for their spouses to start making plans with and unless the source of your inheritance is imminent (ie terminally ill relative), I'd be rather pissed off he was even taking about it.