Sixteen years ago we flew cross country to be with my daughter who had just given birth to twins (by C-section).
Based on my own experience, what she needed most was to be able to take care of her babies without having to worry that her house would fall apart or not having regular meals or that the babies would run out of clean blankets and 'Onesies'. So, in my view, that's the kind of support a new mum needs....she doesn't need another person to take over the care of her babies.
On another note: The more I read, the more I feel you both can go, depending of course, on your DH's level of incapacity.
Most major airlines provide complementary wheel chair service to and from the aircraft, allow priority boarding for the disabled and overall go above and beyond to accommodate a passenger's needs so they can travel more comfortably and with less stress.
Your DD and SIL should consider getting a housekeeper anyway, regardless of your presence.
You don't deserve to be put in such an impossible position....having to leave your disabled H behind, in exchange for what amounts to taking care of your daughter's household. Both you and your H deserve to spend quality time as new grandparents and both of you deserve to enjoy those new babies
Just saying....
