brake

Hi all been renovating a 1995 TRX 300 and have an issue with foot pedal. When applied it's stuck in down position and doesn't return. I removed it and was left with a plastic sleeve attached to the pedal peg. I tried greasing it up and replacing pedal but still same issue. So my question...

My uncle's Foutrax is leaking brake fluid. He says he fills up the master cylinder and its empty the next day. What should I look for on this? It is likely a leaky master cylinder or brake line?