Snipped by me...
FWIW, we don't actually know precisely went on during those 88 days. We have very little information. We know he was keeping her under the bed while he was gone and when people were over, but we don't know what he did during the interim. It's possible that he was doing some things that might have eventually laid the ground work for gaining her trust. Stockholm Syndrome doesn't happen overnight, it's usually gained by doling out tiny slivers of trust and controlled freedom at a time. Seemingly "kind" gestures mixed in with really horrible ones.