Thanks for the medicine advice - i will try and find some threads regarding higher education and medicine.
Chemistry was always a bit of a given, anyway, whether it is architecture or medicine, as is maths. The question has been biology or physics or possibly geography. One of the things that he found very interesting was that of all his subjects, geography was the one he used most during his work experience in architecture. It is nowhere required as an a level subject, but he felt it was directly relevant to what was being done.
Wonder if being a registered young carer would help? DS1 has complex special needs (this is DS2 we are talking about), and while my husband and i do most of the caring, it has been useful at time to have him registered as a young carer.
He has done every first aid course he can find that will teach his age.