You've gotta love some of the situations which come up at tables like that! I try not to offer advice unless it's requested, but sometimes it's difficult to hold back! I have this "vision" (in a situation like yours) of me telling someone not to hit, then the next card is an A, 2, or 3 - which the dealer gets instead - and manages to end up with a winning hand. YIKES
Here's one of my (infamously) favorite hands from perhaps 10+ years ago. I was dealt a pair of 7's against the dealer (5... might have been 6). Either way, it led me down "the path"... dealer ended up with a 21 after I added a couple of doubles to the image you see here... 😞
Tom