Loose impediment in sand bunker.

So, my fellow competitor was in the sand bunker and his ball was lying up against a dry tuft of weedy stuff.  He plucked off the weed and tossed it aside, then played out of the bunker. I questioned that and he said local rules permit removing stuff (like stones) from near ball in bunker.

Should i have asked him to play a second ball, then we could later bring the incident before the committee? And if so, would he need to drop or place, and replace the dry tuft against the ball?

Or simply report his original actions to the committee and let them decide.

The only such authorized local rule allows removal of stones from bunkers for safety reasons, and the rule requires that the committee declare them as movable obstructions in order to implement the local rule.  A tuft of grass would definitely not qualify.

My course has a local rule that stones in bunkers are moveable obstructions.  I think this is for safety reasons.  The tuft of grass or leaves or sticks would not apply.

Carry on with the original ball from where it finishes. Add a 2 sp to his score.

If he  was not sure of his next action he should play two balls following the procedure in rule 3-3 nominating which ball he wishes to count if it was played according to the rule.

http://www.usga.org/Rule-Books/Rules-of-Golf/Rule-03/#3-3

As he was in a bunker the original lie must be re-created as nearly as possible and the ball must be placed in that lie. The tuft of grass is no considered to be part of the lie.

If it is impossible to determine the spot where the ball is to be placed or replaced, the ball must be dropped in the hazard as near as possible to the place where it lay.

He must report his action to the committee on completion of the round.