Confused old boys restored to health (8)
I believe the answer is:
obscured
'confused' is the definition.
('obscure' can be a synonym of 'confuse')
'old boys restored to health' is the wordplay.
'old boys' becomes 'OBs' (OB is short for old boy).
'restored to health' becomes 'cured' (cured of an illness).
'obs'+'cured'='OBSCURED'
(Other definitions for obscured that I've seen before include "Veiled, hidden" , "unnoticed" , "Overshadowed or eclipsed" , "Good news from clinic about schoolboy no longer" , "Concealed from view, made indistinct" .)