Brake message after brake disc and plate exchange, workshop tells funny things

Good day, it’s not about my megane (to happiness) but about the Scenic II of a family member. According to information, the brakes were slow, so the car was brought into the workshop (free). After that, the car was driven for about a day until the brake control lamp started. So let it be checked again to the workshop and the facts. Then received the following statement: – brake cylinder broken – half of braking fluid is missing already – to change this cylinder If you want to protect my family member from a stupidity, you might be able to help here. Clutch and brake cylinder? Is there something to it? Must the Scenic II from 2005 actually be removed clutch (and even gearbox) to get to this cylinder? I mean – the bonnet is already very small from the place, but that sounded pretty funny to me. Thanks in advance.