Can I deduct realtor fee from security deposit for breaking lease

[Amy J.]

Hi all, Located in MI
Brand new to this site and rentals! Our first tenant sucks. 
Person decided to break lease for no legal reasons in first weeks of renting. Person was told you are responsible for all costs until new tenant was found. So we used a realtor to find a new tenant, would this realtor's fee be deductible from the persons security deposit? Because they are breaking the lease early we now have this extra cost due to the persons failure. 
Legally if we deduct this realtor fee would the person have a chance to fight it if they decided to?
the realtor did find a new tenant but the official paperwork is not signed yet. So person is lucky they shouldn't have to pay more rent for next month