Unsustainable mortgage with positive equity

I have come across and EBS case where the borrower is unemployed and has an SVR mortgage of €150,000 on a house worth €250,000.

Employment prospects don't look great at the moment, so he will probably never be able to repay the capital, although he should be able to keep up the interest payments when he gets a job.

EBS have said that the mortgage is unsustainable and that he should sell the house or trade-down.

They presumably would veto a PIA and the borrower is not insolvent anyway, because they can sell the property and have €100k.

Likewise, I don't see them agreeing to a split mortgage. Why should they?

My suggestion is the Deferred Interest Scheme or a long-term interest only solution.

Anything I am missing?

To be honest he should probably sell and buy something for the 100k that way he has no repayments on a house so if he is not working it will be easier. They are obviously trying to get whatever money in they can.
That said they should allow him interest only for a period to see if he gets back to work.