Anyone who thinks they can get away with 3 months of not paying back any kind of credit product, let alone a mortgage, is going to be in trouble. If your friend skipped 3 mortgage payments in a row, I'm surprised they won the case in court. They must have had concrete proof that a bank employee truly misinformed about what it means to miss multiple payments in a single year, let alone 3+ consecutive payments.
It happened to me once. I received an unreasonable bill for building maintenance fees, didn't pay, they sent me a lawyer making more unreasonable demands, I told them to fuck off (after consulting a lawyer myself). The thing is : because I didn't know how much to pay, I didn't pay for several months in a row. I only paid after everything was sorted out. It never went to court BTW, the guy responsible for the mess has been fired and his successor did a great job cleaning it.
This is why he eventually won the case... But the bank was already aware of this, and they were just going through the motions. Either way, be careful.
He did not get his house back though...