As a proton falls into a black hole, it accelerates. How large will its mass become as it approaches light speed?

Very massive objects, such as black holes, can cause the velocity of a falling object to reach speeds approaching that of light. Is a black hole’s event horizon the point at which a falling object reaches light speed, or does this only happen at the black hole’s singularity? If the object is a proton, how large would its mass become at the event horizon? Assuming observer A views the event through a telescope, and observer B is the falling object, how will relativity and special relativity effect the observation of B’s time from each perspective?