apex128

Hello, I have been having some trouble with my brakes lately. They were pretty soft while driving, so I bled them. After bleeding, they feel way better when the car is off, but when I start the car they go straight to the floor. I disconnected my brake booster, and with the booster disconnected the brakes feel 'normal' but when I hook it back up they get soft again. I bled the brakes with my brother many times over again (in the correct order), and even bled the master cylinder a bit. I am at a loss as to what is wrong and really want my car back on the road. Let me know what you think.
Thanks