Concerning those people? Finish getting better? (2,3,4)
I believe the answer is:
on the mend
'getting better?' is the definition.
(on the mend means recovering from illness)
'concerning those people? finish' is the wordplay.
'concerning' becomes 'on'.
'those people?' becomes 'them' ('they' refers to a group of people).
'finish' becomes 'end' (synonyms).
'on'+'them'+'end'='ON THE MEND'
(Other definitions for on the mend that I've seen before include "Making recovery" , "Looking up" , "Becoming better in health" , "returning to health" , "convalescing" .)