AS:
Is it possible that the captain having seen a hole in the cloud, slowed down
and tried to descend while maintaining visual contact with the surface with the
intention of making the final run into LSI low level visual or something along
those lines?
Everything is possible, but I seriously doubt that this is the scenario here. Descent below MDA on a non-precision approach unless you have the runway or the approach light in sight is a big NO-NO.
If that had been a practice, it would have been picked up by my good friend using his HFDM system long ago.