Definitely the latter--she doesn't want to know, because she doesn't care. All she cares about is making her kids comatose while the sun's still out so she and her flying monkey can fuck on the cum-stained mattress next to Bodhi and not have to worry about him being capable of waking up and reporting their fucked up behavior to DCFS.
Susan doesn't want to be a parent. She never has and never did. Jani was absolutely a 'gotcha' baby, and Bodhi her attempt at further ensuring Michael would never ever ever be able to leave her (which obviously failed, but she still uses the kids to try to pull Michael back into her orbit). She was knocking her kids out with Benadryl when they were all of a month or two old because having to actually take care of her children cramps her manic style.
The only reason she fought to hang on to primary custody of them is all the free government money she got monthly for doing nothing more than shoving pills down Jani and Bodhi's throat and handing their drooling selves off to respite workers or the ER whenever they were the slightest bit conscious. Now that she won't be able to keep them as vegetables any longer, she's spinning out of control.