Mates of ours had twins, and also had a 3 year old. We would look after the older child occasionally to give Mum a break, time just with the littlies. We dropped a casserole in once a week or fortnight for the first year. It helped just having one meal that was healthy, and they didn't have to plan or cook. As the kids got older, we now get to mind them too when the older child needs a bit of attention- or Mum just wants to get her hair done without 3 littlies in tow.

We have also gone over for dinner, but taken everything with us. That way, the kids still get their regular bedtime routines and we get to share dinner together without them having to make it all.