My guess is that it was a strategic business decision. He likely needed to continue good relationships with those creditors and employees in order to keep his other businesses rolling along. I have spent my entire professional life in the business/legal worlds and have very infrequently seen people do things out of the kindness of their hearts unless family was involved, though I'm not suggesting it doesn't occasionally happen.
I do object to your assertion that Trump routinely rolls over people. I don't know how you could know that. His employees love him and, as I posted above, I have done business with him and was very pleased with how it went. He has walked away from bank loans that were not personally guaranteed by him, but the banks took that risk when they made the loans. He would not be as successful as he is in business if he treated people the way you suggest. People simply would not do business with him.
I acknowledged that when I said "he might only have $8 billion instead of $10 billion". We're talking about a presidential candidate here, not a ruthless business man - the kind a lot of voters don't trust. I don't trust Trump. You don't have to be ruthless to be successful in business. Of the ones I know, the best businessmen aren't ruthless. I avoid the ones that are.