In that case, I have had situations like that happen, and the tenant may just be out of the deposit. The deposit was a promise to take the apartment, when they pull back, they should have the understanding that they may have to forfeit. I think the landlord should meet him half way and return half.
There was no agreement, no lease signing, just a receipt for payment. The landlord held the apartment for a full month expecting a move in date for the 1st but the tenant was not available at the time. he kept in contact and said he will still take the apartment once he gets back in town. when he returned (in the middle of the month) he said he no longer wants it. The landlord will not return the deposit cause she feel the apartment could have been rented by someone else and its a lost of income for her.