You didn't mention you son's age. If he is 16 or under, he has to take the classroom course, which is offered with two options. He can take the one day classroom course, or the combination classroom and field day offering. If he is 17 or older, he can take the online course without the need for any classroom instruction. But of course, he can also take either of the classroom options if prefers classroom over online, which some people do.
I believe your son can take the online course under the age of 17. He just has to attend a "field day" to get the hands on portions. I think TPWD has a list of locations listed throughout the state. Just find a location close to you that fits your schedule. The online portion is at your own pace, the field day is one day. If he's 17 or older, everything can be done online.