So far as the ppi is concerned, there is nothing to stop you from contacting the companies & getting the necessary claim forms. If they are then completed and the medical people in charge of her care (consultant or GP) write a letter confirming the circumstances the companies should accept this and pay out. In my view, if they did not you would have valid grounds for formal complaint ot their regulator.
Does she have any income at all? If not, it should be possible to claim some benefits, including Housing Benefit to help with the rent. This will not be easy because normally the claims have to be made by the person but, as with the above, a claim ought to be accepted in this situation with the written confirmation of her consultant etc. You should contact Job CentrePlus & the local authority where she lives, or else go to your local CAB & see if they can help.