Transported sick son using mini — ultimately he's close enough to be bussed? (7,6)
I believe the answer is:
kissing cousin
'he's close enough to be bussed?' is the definition.
(buss can mean to kiss)
'transported sick son using mini ultimately' is the wordplay.
'transported' indicates an anagram.
'ultimately' says to take the final letters.
The last letter of 'mini' is 'i'.
'sick'+'son'+'using'+'i'='sicksonusingi'
'sicksonusingi' anagrammed gives 'KISSING COUSIN'.
(Other definitions for kissing cousin that I've seen before include "Distant but familiar relative" , "More or less distant relative" , "Intimate relative" .)