how do you address?

So I'm sitting here at my lovely (and newly cleaned off) writing desk. No, not really a professional writer, but I sit here and write this stuff so I call it a writing desk. Anyway, here I am addressing our holiday letter envelopes, avoiding having to clean the bathrooms (I've done everything from start laundry to pulling out a few dead plants in the garden). And I'm stumped.

One of Kev's aunts has divorced. She's got custody of the two boys. Do I address it to say The Smiths*? Or Jane and the boys?

I'm at a loss.


*some names have been changed