So sorry to hear of these issues.
I totally think it can work.
You don’t have to follow the national curriculum, there’s loads of resources online, like Twinkl etc.
She would have to come on the school run with your younger one unless you decided to home educate both which might be easier to be honest.
I have a 4 and 6 year old and we all learn together and it’s fine. They sometimes learn together and sometimes apart.
In terms of working part time, yes that would be fine, if you can either have a grandparent or other parent have her during that time for play/learning or even take her with you and she can do some work sitting near you or learn something there?
I have met my local he group and the kids and parents are lovely and nurturing and the older ones have been really sweet to mine. It’s nice as they interact with different ages.
I can’t rate it highly enough doing home Ed.
Please stay in touch and let us know how you get on x