Parent on the floor

[scooter2]

In a loose ball scramble, player goes to the floor, bangs his elbow, and begins crying. His team picks up the loose ball, and I blow the whistle to stop play. I signal the coach onto the floor, but then the player's dad also comes out from the stands to check on his son. Both are complaining about no foul being called. I caution the coach to attend to his player, but parent continues to complain. No security around at that time. Should I have instructed the coach to get the parent off the floor? Could I have threatened the coach with a technical if the parent wouldn't leave? Please advise...