We all wish you luck in your project. Is your beetle in running order??
If left idle for 3 months, I shall suggest the following:
Check if battery has juice (current/power/muscle/whatever).
If its weak, take it to a battery shop for a recharge and/or electrolyte change.
Check all fluid levels. Engine oil must be between the two marks on the dipstick.
Check fuel in tank. It must be there in the first place More important, check whether it has spoiled or not. Old fuel has a tendency to turn to a varnish like thingy. Bad for the carburetor and engine. If needed, clean and flush the tank. If not, top with fresh fuel.
Check the brake fluid level. If low or drained from the reservoir, assume that your brakes have given up the ghost and go for a all round brake service with new wheel cylinder washers and (if needed) new brake master cylinder washers or kit.
Above was just a general outline. Details may be provided if you want.
Its good that you are playing it safe by assuming the brakes are bad. Any VW left idle can have bad brakes, especially in a salty city like Karachi. Plus it rained too in the last 3 months.