What to do?

Three months after moving 8 hours drive away my mum (been fighting breast cancer for 8 years) phoned me and told me there is nothing more to be done for her. I have 2 young kids 4 and 7 one has diagnosed ADHD.  Mum has good days and bad days and i only find out how she is really doing when i phone my eldest daughter who lives close to my mum or when i go and visit her once a month for 3 to 4 days.  Mum let it slip the other day and said she was going down hill fast. She wants to end this journey at home and we have promised her that her final wish will be granted as it is the least we can do for her.  Mum has arranged her own funeral, organised a solicitor to be the executor of her will and power of attorney so my sisters and i don't have to worry about anyting.  After all that my worry is not just for my mum but how my 2 young ones will manage being away from school and the back and forth as my ADHDer is having a lot of trouble at school with his learning.  His school is great and very supportive and said that they can send his work by email.  so when school starts again he will be at school for 2 weeks then off a week. I have thought about moving back until mum has started her new journey but the kids miss their dad alot when we are away from him. I will be there for my mum when her journey ends its the not knowing how long ( 3 weeks, 3 months, hopefully 3 years). Do I put my kids first, and feel guilty that I am not with mum and taking some of the stress off my sister who has been doing a awsome job of looking after mum all these years, especially these past few months,or do i feel like a terrible mum for not putting the kids first especially my wonderful ADHDer, I know kids are resiliant and stronger than we give them credit for. I know this is not a huge deal compared to a lot of others out there. I havn't made any close friend in this new town and don't know who to talk to.