Catholics here say that Catholic DOCTRINE teach once a Catholic always a Catholic because the sacrament places an indelible mark on your soul .
So Mel and yes Glenn are still under the authority of Rome and still Catholics ,,no “free will” there
It doesn’t matter what “catholics here” say - what matters is what the church says.
He is considered outside of the church.
Yes - if he decided to return, he wouldn’t have to be baptized. He could simply approach the sacrament of reconciliation.
The Gibsons used their free will to leave and they’re using their free will right not to stay away.