Brake System Question

So I am helping a friend out. The shop told her she needed Hydro Boost Brake System. Can someone explain this to me. She she just need the booster that the master cylinder bolts to?

What are the symptoms?

Wish I could tell you. I found out what the thing is though. Just the ABS hydro unit. The guy at the shop said she had not brakes and that was the problem. She said before hand she had some problems with her brakes being weak but the pads were good.

Rather expensive part to reaplace if it is unneeded though

You must mean the ABS hydraulic control unit. A second opinion before it is repaired may be worthwhile. It could be a bad brake booster which is what bolts to the master cylinder (cheaper!)