Flying alone once is very different to being able to sort out a whole trip for your mum and two siblings, some of whom have special needs.
Based on another thread by the OP from February, there was a lot of confusion regarding the ages of her children. She said youngest is 10, then said he was 8, and then claimed it was because he would be 10 at the time of travel. Fair enough, but this means she was planning holiday that's going to take place in 2027?? She also reiterated they have no money or passports yet, and would be saving up to pay for everyone. However the Tunisia holiday has suddenly been booked and one can only presume it's taking place relatively soon? Not sure package holidays are allowed to be booked years in advance. Where did the money come from between Feb 2025 and now?
OP also disregarded the advice of 90% people on her thread to go to Spain which is a reasonable distance from the UK and a lot easier to get support if something goes wrong.
I think many of the people egging OP on to take this holiday are MN "disaster vulture viewers" who enjoy getting a stranger to put themselves in a situation that can be used for their personal entertainment. They might be hoping for another live thread update or some other drama to follow. This applies very often to dubious advice in medical situations, relationships, schools, children etc.
This is clearly a very vulnerable adult who is trying to organise a holiday that is totally out of her depth of experience. There are very limited finances available, no travel experience, no language experience of the destination country and taking 3 children, including at least one with serious SEN issues who has never been on an international trip either. It would have made far more sense to book a holiday location within the UK or somewhere in the EU with a shorter flight and better infrastructure.
If you read the original thread, the main reason for her holiday is to "get a break from cooking and cleaning" and "take the kids someplace sunny above the grey clouds". Totally valid reasons of course but it's almost a very naive way of seeing it. Travelling with children is not a "break". Most parents know it's more work than being at home because you are in an unfamiliar place without the usual support network. Based on all the facts, nobody else seems to be giving an honest reality check of the situation.