If a friend in my closed friend liked my post on Facebook,Do his friends see my post contents?

[abraXus]

yes, once your close friends like or comment on something you thought was private, their friends can see it too, because then it's considered someone else's activity, instead of just your own

they can also share it, and then you lose control over any privacy settings

facebook isnt meant to be used as a private network, it's a social network

if you want privacy, go back to using email