Overheated pretty bad and the coolant was boiling as the engine was running?

Hello,

An engine can overheat due to several reasons.
It could be simply for being low on coolant, stuck closed thermostat, bad water pump, faulty radiator, inoperative cooling fan or having a clog in the cooling system.

One of the most common causes of overheating is a stuck closed thermostat. When the thermostat fails at the closed position it prevents coolant from flowing. This makes the engine overheat. When the thermostat is stuck, you will have a noticeable temperature difference between the upper and lower radiator hose. One of the hoses will be significantly hotter than the other.

https://www.2carpros.com/articles/how-an-engine-thermostat-works
https://www.2carpros.com/articles/replace-thermostat

Take a look at this helpful guide, it goes over all the common cease for the engine to overheat.

You mentioned the vehicle was low on coolant. Are you able to locate a leak? You could have a leak in any of the hoses or radiator or the water pump.

https://www.2carpros.com/articles/engine-overheating-or-running-hot

Doing a pressure test can help find the leak easier.

https://www.2carpros.com/articles/radiator-pressure-test

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.