I'm with GN on this one. Have seen at least one guy go properly florid paranoid delusional after steroids (admittedly he was on high doses for a medical condition) requiring big doses of heavy sedatives to control him. Fortunately, this was not in the air (it was in hospital so ready supply of sedatives and people to give them!) so I would be quite surprised if the CAA were to approve a licence in someone using them 'recreationally'.
Nasal steroids to control nasal inflammation and reduce symptoms of sinusitis are fine from that point of view. Your colleagues problem might be an issue if his sinusitis is not well enough controlled for him/her to clear their ears. Doubt it would interfere with the granting of an initial licence though