I would just say - you're welcome to join us at my folks place - and then just leave it. If she wants to come along she can. If not, go yourselves and have a nice time....
T 13 M 7 Me 48 H 46 SS 15 BD 7.14 PA D final 5.16 (H filed)
We receive & we lose, and must try to achieve gratitude & embrace with whole hearts whatever of life that remains after the losses - Dubus