Acknowledged Henry was unwell (6)
I believe the answer is:
hailed
'acknowledged' is the definition.
(I've seen this before)
'henry was unwell' is the wordplay.
'henry' becomes 'h' ('H' can be a synonym of 'henry').
'was unwell' becomes 'ailed' (I've seen this before).
'h'+'ailed'='HAILED'
(Other definitions for hailed that I've seen before include "Greeted like old Romans did Caesar" , "Greeted like ancient Romans" , "acknowledged" , "Came down in frozen pellets" , "Called out to attract attention" .)