Hmmm, not 100% sure about this, but i think its unlikely you can claim housing benefit to pay the mortgage on the house your living in...as otherwise we'd all be doing it
Worst case scenario is that you end up claiming Income Support as a sick person and then there is a qualifying period usually 39 weeks before the interest is met on your mortgage by IS. This period is changing next April on Job Seekers Allowance to 13 weeks, in response to the credit crunch and people struggling to meet their mortgages.
If youre claiming IS however, depending on the rent being offset by the mortgage you have to pay out, the income from the other property may be disregarded..and would not affect your entitlement. The capital value of the property may also be disregarded, if there are divorce proceedings preventing the sale of the property or indeed there is no capital value (negative equity).
I would always advise speaking to the the local CAB or welfare rights group in your area, as they will be able to provide more tailored advice.
Hope your on the mend soon though.
Kind Regards
SG