junior lender forecloses - is he responsible for the...

junior lender forecloses - is he responsible for the first?

yes. still responsible

I wouldn’t say responsible. The first remains secured by the property, so they will likely have to pay it if they want to resell the property - but they don’t have to, and they have no responsibility for doing so. They could simply let the first foreclose - though they would lose their rights in the property if they did.