Well, she did the favor for you. Not for Abs, not for the boys, though they are the direct beneficiaries of the gifts. It's not inappropriate to thank her yourself. It would be additionally nice to be thanked by Abs, and she's capable of understanding and doing. How much help/support/motivation is needed to get that done... I don't know. I'd be fine with getting the card and asking Abs directly to sign it after you've shown her the haul. Of course she'd sign it.
my two cent's worth.
