force or not at 1st base

Question
my son was playing first base.  batter hits the ball up in the air, son catches ball then drops, still batter not at 1st, son picks up ball then crawls to 1st and touches 1st base with glove, ball was in other hand.  Ump called the runner safe because he didn't touch the bag with the ball.  We think he should have been out since it's a force, the ball was in his possession and when you tag first base with your foot you are touch the ball to the base.  what's the answer to that?

Answer
Very good question, very good umpire.....Take the "foot" out of the equation for a moment.  What if it were not a force & happened at second base?  You would agree that the runner would have been safe correct?, because the empty glove is not an out.

So it has nothing to do w/ a force or what base.  The batter runner was safe.  Either the ball has to touch the runner, the base or the foot extension.  One of those screwy things, but an excellent call.

Thanks for teh question.

Andy