It could be that the school are not extremely skilled in identifying potential and thinking creatively about how to nurture it. If they are just going to state which courses he is likely to be able to succeed with, then it doesn't help you at all with his emotional health and helping him to manage it.
I would back off from giving careers-type advice...... and leave that to school. I worry, and saying it from being a mother of SEN ASD child, that you might find it a struggle to manage being accurate and realistic with supporting his morale. I've just found from friends who are mums to higher functioning SEN teenagers that the 'be realistic' conversations rarely go as well as the 'youre fantastic with a host of skills' conversations.Especially if the kids happen to be entering a sort of separating, finding their own identity phase. Why it be you who does this guiding ; I would just be unconditionally loving and be a bit subtle:
I would encourage the practical activities, as he might really love these, once he gets into them, and be less interested in university research. There are lots of fascinating courses, eg at Capel Manor, here in London, and hopefully where you are - and Entry Level.
A good tutor could also be a mentor and help with the guiding and reinforcing confidence and self-belief. Maybe a twenty-something graduate, who is young and near to his age. So if you hear of a good tutor - or go on Tutor sites to find one - maybe this will be good for the mentoring.
I think lots of volunteering will help him, from another angle, find out what he is good at and enjoys - in the way of soft skills, etc