[Xx_jet_xX]

Considering the circumstances, and its a ladies watch and also a bracelet, my first suspect is your brothers girlfriend who was there that day. both items are something a female would covet and even notice lying about in the lounge, and a male would most likely glance at and forget 10 seconds later. now if it was something like a cool knife or something of that nature then the male would probably grab it and the female ignore.

Just because she is an adult doesnt make her better than a teen or even a child. Adults are thieves and liars too.

Best thing to do is if both those friends are around is mention the watch in a passing comment along with who gave it to your mom and how upset she is that its missing and watch their reaction. The guilty party will show themselves because they feel bad over what harm they did because they thought it was just an expensive watch and not an heirloom. The showing will be subtle such as they wont have much to say in the next conversation and wont look you in the face much less eyes. Also hint that you sure wish you could find it and give a room in that statement: "Dam I wish i could find that watch that my father gave my mother in the lounge" this will give them a way out without telling you direct that they did it, and an opurtunity to place the watch someplace in the room specified the next time they are there.