it's the quadriceps muscle, the big one in the front of the thigh
recovery depends on the degree of the tear, and where the tear is located
if it's in the middle of the thick part of the muscle, it will probably heal by itself in about 4-6 weeks
he'll need those painkillers and crutches, muscle tears are agony
if the tear is anywhere near the muscle's attachment at the knee, it may require surgery
how old are your DD's?
he may be able to hobble around in a few days
meanwhile, you should be able to see where the tear is located - it will be the most swollen area and may have bruised
apply ice very diligently, in fact, you could try ice massage: using a flannel, hold some ice cubes so that the actual ice is touching the skin of the thigh, and your hand is protected by the flannel. Rub the painful area with the ice for 5 minutes. Keeo the ice moving all the time. It will get cold, then achy, then burn and then go numb - it doesn't feel all that nice but really helps with controlling the bleeding inside the muscle, and with swelling and pain. 5 min doesn't seem very long but when you're doing it, it's a long 300 seconds!!