This seller looks like a car flipper, so he probably doesn't know squat about it, nor cares as long as he can unload it for a profit. All the reason to be very very careful
. Very rough interior and the rust will be expensive to repair (plus the rust that's covered up that you don't see), plus new paint.
The other costly question is the condition of the fuel injection system. Old worn-out injection pumps can leak fuel into the engine oil, yet actually run pretty well. However, a leaking FI pump downs the car because you don't want fuel mixing into the engine oil. Beware if it looks like it has a very fresh oil change. That could be an indication of trying to hide a leaking injection pump.
The cost to rebuild the injection pump and maybe the thermostatic actuator is almost $1400 alone, not including labor to take it off, put it back on, and tune it . . if you can find a mechanic locally that even knows how. That can make your $2500 car expensive in the extreme by the time you fix the rust, repaint it, and rebuild the injection pump, not to mention reupholstering the entire interior, replacing a dashboard that's in really bad shape, or any other mechanical problems . . . like bad syncros in the transmission and the already admitted to bad brake system.
Not trying to rain on the parade here, but as a first time Alfa owner, it's almost always better and much cheaper to buy a car in very good condition.
Read this guide on assessing the fuel injection system before you go look at the car.
Pre-Purchase Inspection of a SPICA Injected Alfa