sustainable and non-sustainable mortgage, cooperating and non-cooperating borrower(s)

What are the implications of the mortgage being sustainable or non-sustainable? How is it determined?

If I have repaid all arrears and the 2nd borrower is still not engaging, can I still be deemed non-cooperating and the mortgage be deemed unsustainable (even if I pay in full for the past few quarters)?

Nec;

Non sustainable is determined when account goes into serious arrears and the income of the borrower cannot support it .
eg income 3,000 less mortgage 2,800 would be unsustainable.
Sustainable may be income increases to 5,000 mortgage 2,800 .

If you have paid all arrears the Bank have no issue, they may huff and puff but if you are up to date then all is well in their books.
If 2nd borrower is not engaging he/she may be non c0-operating but as long as Bank is getting paid , they have no strong gripe.
You as payer are obviously co-operating.

Good Luck.

I got a frozen feeling after reading your post. I am really scared. thank you
I hope this will all end well.

Nec;
Do not freeze, do not be bullied , check other Ask About posts ,you will be surprised at good info in them.