Obviously the vet is the right place for such a severe condition but are you able to throw any light on the background?
Has your boy shown any other allergic symptoms over his lifetime? Have you had any environmental changes recently - inside or outside? Did he go from zero symptoms to very severe in a short space of time, or was this a gradual decline?
This info might help others to help you but in the meantime have you spoken to your breeder? Many good breeders will have knowledge of all the conditions that
may affect their breed even if they have no direct experience of the condition or severity you describe. They also have a pretty extensive network to see if anyone else can help.
My lad goes through phases of gummy eyes (allergies) and if I don't keep them clean for him he'll rub and scratch til he is sore. In addition to eye gel from the vets, when needed, I've added a basic maintenance step which is to clean them with a pad moistened with colloidal silver. I'm new to colloidal silver but if you search on here you'll find a couple of recent topics covering it's usage on soft membranes. Edited to say: you may want to check with your vet to ensure it will have no adverse reaction to any treatment already prescribed
HTH
Kindness is the language which the deaf can hear and the blind can see ~Mark Twain