It sounds like you are going to have to remove the front plate and pull out the radio and check the connections. Most likely "the kid" disconnected some of your speaker wires while pulling out the subwoofer and his amp. His amp was probably wired to the soundbar, and he probably didn't connect the wires back to the radio. You will have to connect the speaker wires back to your radio. Most speaker wires have a strip down one of them. This allows you to tell which is the positive and which is the negative. All stripped wires on the radio "must" match, the stripped wires on the speakers. Each set of speaker wires must match a set of radio speaker wires. Each set is normally one color, each set with a stripped wire.
Also, you will want to remove the speakers enough to check the terminals on the back of the speakers. One terminal should have (+) and one will show (-). The striped wire is normally connected to the negative terminal. All stripped wires "on every speaker terminal" must be connected to the same terminal. Otherwise, your speakers will be out of phase. Normally the speakers wires are color coded too. One set might be green, one set might be black, one set gray, one set red(four speaker scenario). Each set will have a stripped wire. If you forget the colors, it doesn't matter. You can fix that behind the radio. Its called "fixing it in the mix". Just make sure to connect all the stripped wires to the same charge (-).
Once you have this done, and the wires are connected properly to the radio, you can check the fader and the balance.
Fade fully front, balance fully left, and you should hear only your front left speaker.
Fade fully front, balance fully right, and you should hear only your front right speaker.
Fade fully rear, balance fully left, and you should hear only your soundbar left speaker.
Fade fully rear, balance fully right, and you should hear only your sounbar right speaker.
If you find that a fade/balance position is not sounding the proper speaker, you can move that speaker wire set to the proper radio connection. Just make sure you keep each set together, and each stripped wire to a stripped radio connection.
If you have all the speaker wires connected to your radio and your speakers, and you don't hear anything from one of the speakers, then likely you have a shorted speaker wire, and it will have to be changed. Hopefully, this is not the case, and the problem is just the connections.
Make sure that you aren't mixing colors. I mean its okay to pair a green set of speaker wires, with a black set of radio speaker wires. Just don't mix a red and green speaker wire, with a black set of radio wires. Keep one set of speaker wires, going to one set of radio wires. Otherwise, you might mistake this error for a shorted set of speaker wires. Also, don't pull the wires, or you might short them yourself.