Honestly based on what you are describing DO NOT attach any battery to the car for your own safety. It could be the battery but usually if a problem occurs there, only one or two cells would go at once causing a drop of around 1.5-2v at a time. It could be possible that the charging system fried it if there is a problem. But I’d find it hard to believe that it completed shorted all the cells in the battery. Considering the car was running ok a few hours ago.
However, based on the fact it started boiling just when trying to charge it seems to indicate a possible short. So DO NOT connect a battery until you test for that first. Last thing I want to hear is a story about an exploding battery and a missing face.
Attach an ohmmeter = without any battery in the car from the positive and negative terminal. It should be next to infinite with the key off, if it isn’t or it’s near 0 then you have a short somewhere. Look at that first. Most likely though your battery is now toast.