There is not a simple fix, sorry to say. The green is most likely switching modes because the crystals are out of alignment. It's possible to fix, but you would need optical or thermal adhesive to put the crystal assembly back in place after realignment, and a setup to make sure it doesn't move whatsoever while drying. And also glasses that block 1064nm since there will be many stray reflections.
In short, sorry for your loss, but buy a new green laser.