Given the petulant post previous to this I think some posters might consider the the issue here is that the apple has not fallen very far from the tree...
Ok I'm going to apologise for that as it is harsh and I understand that you are very upset, emotional and worried about your son.
However, you are not helping him if you put the blame here on the Uni.
By the point he will have received notice of termination the language will absolutely NOT have been "fluffy" or kind and rightfully so.
It would have been direct and factual in order to make your son wake up to the severity of a situation he had previously chosen to ignore for some considerable time.
Likewise any letter overturning the termination, explaining the expectations of him continuing his course will equally not have been sugar coated.
The truth is that your son skipped past every offer of support, kindness and the opportunity to engage constructively to the point of crisis and blunt talking.
Moving forward I'd be asking him why he ignored the emails? What support does he need and is he going to make the effort to access it?
I understand why you might not want to give details, but it's hard to be specific without them other than saying that IME (especially post COVID) Uni's and the SU are very cognisant of supporting students but they have to be willing to engage.