No end worried about them recovering (2,3,4)
I believe the answer is:
on the mend
'recovering' is the definition.
(on the mend means recovering or recuperating)
'no end worried about them' is the wordplay.
'worried' indicates an anagram (worry can mean to interfere with or disturb).
'about' is an insertion indicator.
'no'+'end'='noend'
'noend' anagrammed gives 'onend'.
'onend' placed around 'them' is 'ON THE MEND'.
(Other definitions for on the mend that I've seen before include "Recovering from an injury or illness" , "Regaining health" , "Informally getting better, improving after illness or accident" , "Improving in health" , "Looking up" .)