Wow look at you!!! That's fantastic and Saturday gives him less time to set a plan in motion to stop you. Can you not tell him until Saturday (pref a few hours before)?
Reading your post is like a trip down memory lane for me. The second hand anxiety from him catastrophising. The world was always ending we were always going bust. Trying to make me feel less safe (easier to manipulate) and stop me ftom doing anything I wanted in the business.
The hassle about any trip and not being able to afford to do anything (eg hire anyone that made my life easier) but magically we could afford things that made his life easier.
If he's so worried about money perhaps he could get a job? That's what people who are worried about money do.
I hope you are starting to see that the games never stop, not even for a second. I know you feel like you don't have options but maybe that's because he made you feel like that. Because you do really.
Your mum sounds amazing. I'm so glad you are going, and he will pull out all the stops to prevent it because he knows she is on your side. I'm think heart attack/panic attack. Possibly a hospitalisation, or at the very least doctors orders to stay in bed. Maybe a back sprain?
Or there will be an emergency which requires you to return, almost certainly child related. One will be 'seriously injured' or 'very unwell' because he knows that's your weak point. You aren't going to ignore a sick or injured child and he knows that. So you will rush home only to find it's not that bad and he will be indignant and angry if you say anything.
They are YOUR CHILDREN, kind of thing. So think about how you will head this off at the pass. Make a little backup plan with a friend here. And enjoy the lovely weather and seeing your lovely mum. She sounds wise and she ONLY cares about you.
Do you think you could start your business from there? No wonder he wants to get her in the UK, he wants her under his control.
Honestly it's just ridiculous how predictable he is. No fucking imagination at all. You are twice the person he will ever be and I hope you are starting to see that.