I find it hard to peg MB...yet. I do have some empathy for a mother who might perceive her son has been wrongly accused, and who responds by circling the wagons and providing support as she sees it. DM is wildly, wildly manipulative and a mother is perhaps willing to fool herself longer than some. This has to be a nightmare for her. He is her only child. But, granted, everything she's known to have done so far raises at least a little contempt.
I may have had a little sympathy for her as a mother if she wasn't part of wiping finger prints and if she didn't continuously and knowingly break a court order.