Hi there,
The lender has to (legally) make sure that the person getting the mortgage has mortgage protection insurance (mpi) in place EXCEPT in certain circumstances & one of the is if the person getting the mortgage can't get mpi. However, that is not to say that they have to give your friend the mortgage either - they can refuse to give an otherwise approved mortgage on that basis.
Your friend might do well to talk to a few brokers (or someone here may be able to advise) to find out which lenders will waive the mpi requirement in case where borrower cannot get it.