Trying to do a word sum for <rehabilitate>. It looks like
re + habile + it + ate
But I can't find any evidence for a suffix <-it>. There are 167 words in the Searcher that end it <-it>, but none of them are clearly a suffix, but I'm not sure about words such as "admit" and "debit." Perhaps it is a suffix there? My dictionary does not list it as a suffix, not that that counts for much.
But perhaps <habile> is not the base at all, though -- there are no words in the searcher with <habil> other than those based on "rehabilitate." But I can find other words in other sources, such as "habilliment" and "dishabille" though that has a double l for some reason.
Anyway, any help would be appreciated.