If it was me, hybrid I would be back at the doctor, expressing my concerns.
If his condition is noted on his personal information, the school should be aware of it and taking it into account. If not, time to let the school know and request a meeting with the headteacher.
As for undiagnosed asthma, as usual, I have a tale to tell.
In my last year at university, I became very ill had a persistent, barking cough, breathlessness and was generally unwell.
I had all sorts of tests and was eventually told I didn't have asthma, that it was just nerves and told to pull myself together.
By the time I was six stone and newly married, I was too ill to work. My mother made such a fuss that my GP decided to refer me to another hospital, a teaching one in Glasgow. I went and had all sorts of investigations and returned the following week for results to be immediately admitted to intensive care. I was in there for six weeks, got out on Christmas Eve, only because I cried so much, they were afraid I would make myself worse.
I was diagnosed with brittle asthma, which is a killer. My wonderful consultant told me that I would have died if I hadn't been admitted. The scary thing was my mum and husband were sent for and told to prepare for the worst.
Yet here am am, still getting on with my life, because my mum made a fuss.
Please don't think I mean your grandon will die of asthma, but something has to be done to give him a better quality of life. He can't do it, so others have to fight his corner.
I will now get off my soapbox! I really hope you can all get support.