Should I be able to hear game sounds on the these bluetooth wireless headsets? Both of my sons are set up win these headseats yet only the 1st player can enter in or hear the chatting with online friends. Shouldn't they be able to hear each other and the chatting?
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, see the FAQ.
I'm going to guess that you are using the Xbox branded Bluetooth headsets since I'm relatively certain these are the only ones that work (unless you're using USB Bluetooth headsets). It is possible to get both players to talk online as described here. The article explains how to do it with wired headsets, but the process is the same.
There is an important restriction to having both players use headsets: they both must have an Xbox LIVE Gold subscription. If one player is a guest and does not pay for Xbox Gold, they will not be able to chat at all. If this is the case, you would need to purchase a second Xbox LIVE Gold account in order for both of your kids to talk online while playing multiplayer games. Sourced here, here, and here.
Also keep in mind that the two players will not be able to hear each other through the headsets. Presumably this is because they are sitting next to each other, so hearing their voice both in the room and in the headset would be silly.