Your son is training at a Gliding site ?
Does he fly Gliders ?
If not ? Why not?
With a BGA Glider Pilot Licence ( Bronze With X/C endorsement) already has enough hrs to convert to a NPPL.
Has he had a CAA medical ?
There's no point spending money unless a Class 1 can be acheived.
I think you need to do more research into how he could achieve his ambition at minimum cost.
When he's finished his Degree and worked hard to get top grade why not try to get an Airline to sponsor.
You never Know there maybe a place for him !