Your son’s health and well-being come first.
Get it written down, how it makes him feel, having to walk that distance and stand and wait in the cold, get him to be explicit. Any heart fluctuations, muscle/joint pains, limb weaknesses, circulatory issues (numbness, tingling, painful cold extremities, etc), autonomic issues (fast heart-rate, poor temperature control, inappropriate fluctuations in blood pressure, inappropriate sweating, etc), any respiratory issues, brain issues (brain fog, confusion, lightheadedness), check out Dr Diana’s symptoms checklist and ask him which, if any, he experiences and at what points in his journey. I would also mention the fact that he’s more vulnerable than most, due to his restrictions.
I’m sorry, I don’t understand how the authorities work over there. Is there no-one who could act as an advocate, say a childrens group, or a charity, or a government disability department, or something – you need voice-power.