What baby needs is to sleep with family (6)
I believe the answer is:
napkin
'what baby needs' is the definition.
(napkin can mean a baby's nappy)
'sleep with family' is the wordplay.
'sleep' becomes 'nap' (napping is a kind of sleeping).
'with' is a charade indicator (letters next to each other).
'family' becomes 'kin' (synonyms).
'nap'+'kin'='NAPKIN'
'is to' acts as a link.
(Other definitions for napkin that I've seen before include "piece of material giving consumer protection" , "Protective cloth square donned during meals" , "Small piece of table linen" , "Protective cloth square worn during meals" , "Cloth used at mealtime" .)