Runner Picking Up Live Ball

 
With no outs and a runner on second base (R2), the batter (B1) doubles into the outfield. R2 attempts to score and slides home on a close plate. However, the catcher drops the ball and it rolls about 5 feet from home plate. After R2 scores, the helpful R2 picks up the loose ball and hands it to the catcher. By the time R2 handled the live ball, B1 was standing on 2nd base watching the action at home.
 
The defensive coach wants B1 declared out for R2 interfering by handling a live ball. What does the umpire do now?
 
Call
In the play below, R2 is safe at home and his run counts. Since R2 handled a live ball, the ball is immediately dead. If runners are not attempting to advance, there is no penalty. If a runner was attempting to advance when the live ball was handled, then the runner who the catcher would have made a play on is declared out.