After touch down, when I hit the break the front wheel sinks into the ground. Is this accuate in RW?

It's probably because the front gear isn't fully animated but the main thing is that the fuselage should be sinking realisticly. You could stiffen up the front gear by reducing static compression to say one foot or so if it is already more than that and then reducing the wheel height by the same amount that you reduced the static compression by in the Contact Points section line one, in aircraft.cfg but it might cause other problems like bouncing even when taxying. If it works OK you could also increase the compression ratio (max is 10)to lessen the amount the wheels sink but test with the plane empty as well as fully loaded. As long as you note the original settings you can put them back if you mess it up. However, as long as the wheels sit on the ground properly at rest and the plane flies OK I'd say it's easier to leave it alone.

Yes. Aircarft cfg- all the way to the bottomChange BRAKES from 3.5000 to 0.5. Problem disappears.