Living alone should not make someone’s time the group’s unclaimed resource.

A household of one gets read as a schedule with room in it. The late shift, the airport run, the holiday cover, and the long stay with a relative all drift toward the person assumed to have fewer competing claims. Their evenings are just as full of a life, but that life has no witnesses to make it look official. Availability gets mistaken for willingness.

If you organize things, ask that person the way you would ask anyone with a family waiting at home. And if you are the one being asked, you can say the evening is already spoken for without explaining what it was spoken for.