I suppose you could argue giving money to any cause is "taking money from the NHS" as there is a finite pot of money and taking money out of it to spend on one thing means less money for something else.
Governments tend to spend money on things that have political impact. The higher the political impact the more money is generally spent.
The NHS has high political impact. But so does families having their houses repossed and them kicked out on the street. No government wants large numbers of repos - it's bad for business.
The real question is how best the government should prevent this, either through direct wealth transfer to mortgage holders via tax offsets or through loans/grants/government equity stakes that are redeemable once the payment difficulty period is over.
Given the fact that successive government have constantly meddled and subsidised the housing market over the past 2 decades in order to maintain high house prices and prevent a much needed correction in prices, it's not clear to me what action they might take going forwards. Offseting mortgage costs against taxation will be yet another sticking plaster over a fundamental problem - house prices that are too high.
The question is whether this government feels this is the time to stop trying to prop the market up against economic headwinds and actually lets the market find its own level or wants to pass that hospital pass forward onto someone else.