Oh dear, difficult situation. Is there any reason why she is negligent? As in does she suffer from an illness or something.

Anyway, regardless, I think you and hubby should talk it out with her and tell her about your concerns. I mean, if you are silent about it she might not know she is doing something wrong and/or will never change. Talking about it might bring some realisation (on her part) of her actions and thus, give her a chance to change for the better... if she wants to. Also, you both (hubby and you) will not keep this 'inner' resentment.

So do talk it out with her, but without being confrontational about it. See what she has to say. If she is all brazen about it, you might reconsider letting her have your daughter. I know I would be wary in this situation.