Yeah...it will feel awful.

Not much youcan directly do.
Depending on how aware he is of the problem and what the nature of it is, keeping mentally active with things like puzzles etc may slow it down, but its kinda late to make such changes but may be worth seeing a doctor about.

Be strong,
Don't be all stereotypical silent suffering Scandinavian - talk to people (friends, hopefully councilors at uni, a priest if that's your deal)

i wish you all the best, PM if you need,
And you have my sympathies