He needs a USA Wrestling Card Number (and you have to pay for that) for insurance purposes and/or before you sign up for tournaments. Also, 4 years old is a little early. The attention span during practice with 4 year olds is very short (maybe 30 minutes to 45 minutes) and they tend to want to blow the coaches whistle during practice or play games often. That is very normal. The kids of that age in the room are ussually siblings and kind of roll around with the older kids during water or bathroom breaks. We require our 5 and 6 year old parents to hang around in case their child is being over disruptive to the practice room or they may be put in time out by the coach.