Cabin pressure on Real Tonga aircraft?

Dear travel community,

Can anyone tell me if the type of aircraft that Real Tonga uses to fly to Ha'apai (or other islands in the Kingdom, for that matter) has pressurized cabins?

Someone in our travel party has received medical advise to only fly on aircraft with cabin pressure (as most commercial airplanes have, but I am not sure about the probably small planes that make short flights between the island groups).

Any information will be very helpful. Thanks!

Smaller aircraft, usually propeller types, that dont exceed 8000ft -12,000ft altitude, dont have a cabin that is pressurized, as they dont need to. Island hoping planes, or "puddle jumpers" do not have pressurized cabins. In fact, they may have windows open in the cockpit, for fresh cool air.

https://aviation.stackexchange.com/questions/25746/when-is-an-aircraft-required-to-be-pressurized

https://aerosavvy.com/aircraft-pressurization/

Thank you mrmoto. I am looking for definite information about whether the specific aircraft used by Real Tonga is pressurized. I am guessing probably not (also based on your information)... but would like to be sure.