If the fire occurred through the negligence of another person, he can claim against that person.
e.g. if the landlord failed to ensure that the property's wiring was in good condition, he can claim against the landlord. Or, of the person in the upper flat left a chip pan unattended, he can claim against that person. (In either case, the negligent person can pas the claim to their insurer - if any - under their 'third party' cover. If they've got no such insurance cover, they will be personally liable).
Chris