does this landlord have the right to withhold deposits?

Tenancy Deposits

Hi
i am making an enquiry on behalf of a friend of mine who asked for advice regarding his deposits. he signed up to take a room with a landlord in late july of this year and left 6 weeks deposit to hold the room and the balance of rent to be paid on moving in. At which time he would also sign the necessary contracts. Unfortunately for him, on his move in day he injured himself and couldnt' move in but was still interested in moving. As it turned the injury was quite severe, he ripped his achilles heel and had to be hospitalised. this meant he was on crutches. he had initially told the landlord he wished to proceed when he thought it was a minor injury however by teh 30th july when he was told he would be on crutches he told her he could no longer take the apartment. She said she would need to be compensated for which he offered two weeks rent, however the landlord is refusing two weeks and instead has decided to hold onto four weeks deposit and states that she has a right to do because of breach of contract? even though he didn't actually sign the contract. she claims she has had legal advice and has a good case to answer for as he would be liable. What rights does he have? No deposit was registered with any deposits schemes? Look forward to any helpful responses.
Regards