BRAKE FLUID

No, they do not need to replace the brake fluid.

brake fluid is hydroscopic (absorbs moisture) and most all car manufacturers advise flushing the brake fluid every 2-3 years. whenever you replace a hose, air will migrate into the system and eventually cause problems in the calipers, master cylinder or abs pump. the vacuum hose is one issue; they likely noted the color of your brake fluid and advised this as a separate service.

You will not need to replace the brake fluid. If anything, check that the fluid level is ok. If you need to top up the fluid, ensure that the proper type is used. Eg. DOT 3. Refer to the cap or the operators manual for correct type of fluid to use.