While the enthusiasts are making an unofficial patch, I tried to fix a firefighter with my own hands and minimal knowledge. Completed 12 firefighter levels on the second island, at the very beginning of the game. To get to the second island at the very beginning, you need to take any boat and swim to the golf club and stand against the downtown, where there is a pier with stairs and manage to swim to the pier before the shark eats you.
Don't forget to keep an eye on the police and peds who will attack you after extinguishing them, try to be on the move. (I do not know how to solve this problem).
Installation: Replace firetruck.c is at the root of the mod folder on the path: C:\Games\GTA Vice City NextgenEdition\common\data\cdimages\script_sources\test\script_vcr\convert