Death by Antifreeze?

So some lady in New Jersey apparently (and allegedly) offed her better-off brother-in-law by giving him a fruit smoothie laced with auto antifreeze. And both the prosecutor and defense attorney agree the crime was based on pure greed (she supposedly wanted to make her brother-in-law sick so he would have to move in with her and her husband so she could control his finances).

Well, I've been poor more than once in my life, but I can't say I begin to understand this one. How does a person even conceive of it?

She's claiming mental illness and is being held on a demand for half a million in cash bail. Well, at least she wasn't ill enough to come up with the plan.