Belonging to that man (3)
I believe the answer is:
'belonging to that man' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for his that I've seen before include "that chap's" , "That man's" , "Belonging to that man" , "It belongs to him" , "To - Coy Mistress (Marvell)" .)