DD1 is 9 and started middle school this month. Her older brother is in year 7 of the same school. DD is HF ASD and has an official diagnosis, her brother has lots of traits but no diagnosis. DD is apparently settling well in school - but she is struggling with the walk to and from school a bit. I have a younger dd in year 2 so I cannot take the older ones to school - dh has a long commute by train but he does sometimes walk with the older ones in the morning (part way to school) We are a short distance from the middle school 10-15 min walk.
Yesterday I asked the older ones to meet me at a coffee shop near their school in the afternoon instead of going home, as a treat I promised milkshakes. DD had had a difficult day. She had an Occ Therapy review assessment in the morning and she did well and has been discharged from the OT (she took the word 'discharged' badly though and is feeling rejected). We were both a little stressed getting her to school after the appt, and she missed the school photo session which upset her, she struggled to ensure she had all her belongings at the end of the day and as her teacher was with her then she got into trouble with her teacher for not switching her phone off in school, as it rang (my fault I called but it was outside of school hours so she should not have been told off). So then she was late meeting her brother - he got stressy trying to drag her to the coffee shop she was yelling at him about the way she had to walk home (she was convinced she had to avoid crossing the road - ds and dd knew they were meeting me).
I spoke to ds on phone and heard dd going into meltdown, so rushed to meet them. Poor dd was distraught - really wanting a milkshake and really embarrassed that she was all shouty and shaky - it was heartbreaking. 
so she wanted to go home and go to the coffee place - I just really regretted having the idea in the first place - it was absolutely the worst day to do it.
This is not ususal but ds has had to put up with/ manage dds tempestuous emotions before, to and from school. He has been amazing even having little races with her to encourage her to speed up and beat him home! She has made him late to school once though which bothers ds greatly and is stressing him out.
Not sure what to do? Do I get the school to come up with some support, find a way to pick up and take dd to school myself? DD2 needs support as well and I don't want to neglect her needs or ds. It just seems that dd will probably seem to be doing great at school and then take all the pent up frustration/ stress on ds and I cannot allow that. Help.