I am Dr Mbong. Skiing though enjoyable like any other exertional activity, is associated with rapid breathing which may cause ingestion of too much oxygen
and a medical condition called respiratory alkalosis
Respiratory alkalosis can temporarily cause the dotty vision and nausea
. The hurting eyes may be due to the effect of rapid passing wind on his eyes as he speed off while skiing.
On the other hand if the ski site was at a very high altitude, the oxygen concentration of air may have been low and he is may have developed a condition called respiratory acidosis
(the opposite of alkalosis) which may cause the nausea and equally dotty vision.
I advise he rests, takes lots of fluids (preferably natural fruit juice), avoids light, electronic appliance screens, TV etc and the symptoms will subside. If they don't after 48 hours, see a physician.
I wish him quick recovery.