Universities do go off school's predicted grades, so if he is heading for a prediction well below what he needs for his chosen course, there are two things he might want to do:
Talk to teachers to explain and ask if a higher prediction is feasible
Look at other uni options which don't have such a high requirement.
IME schools will often raise a prediction if they think it is reasonable - for example if the exam it is taken from was very challenging for all, or if the student had extenuating circs such as illness.
Otoh it's not helpful to be over-predicted. A contemporary of DD's begged the teachers to raise her prediction as she needed (from memory) BCD to get where she wanted to go; so they did it, she got her offer, and then achieved CDE in the exams so had to rethink anyway.
A mate of DS's had predicted well below the typical offer of his ideal course, but he applied anyway and was not surprised not to get an offer. The course demanded I think AAA; his predicted was BCC - which is what he got in the end anyway.
I should add that in both these cases the student ended up studying somewhere they were happy - but in the case of DS's mate it was an easier process bc he knew all along that he wouldn't get an offer from uni A, so was realistic and et his sights instead on (perfectly good) uni B. DD's mate had to do all that on results day via clearing which is always a headache. I speak from experience there!