I would venture to say that it was your former h that reached out to the children. He could have had a moment of clarity. If the wife reached out, it could be that your former h is having some health issues and thought the children should be advised.

My question would be...did the individual state why they were contacting the children?

Whatever the reason, if it's important, the individual will attempt to contact again.

Sit quietly, the answers will reveal themselves when you least expect them to.
The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.