B.R.
Our homeopath recommended we use a cup, or more depending on hair length, of olive or veggie oil with a drop of Tea Tree Oil (optional. Lice don't like the smell though the olive oil does the job of smothering just fine) mixed in with it. Cover the head and hair with this mixture and then cover the head with a plastic shower cap. Leave this on for at least half an hour then shampoo. The dead lice will come out in the shower. You can do a final rinse with Apple Cider Vinegar being careful not to get it in the eyes. This will help loosen the nits that you will have to comb and pick out of his hair. I found that shining a flashlight on the hair helped to find the nits. They reflect in the light.
Repeat this every 3 days after that about 3 more times. This will assure you that any nits you missed won't hatch and lay new nits.
This method worked great when my oldest was 2 and got lice at his daycare. The over the counter products you can buy are a pesticide. They don't work all the time and why risk adding that chemical to you little ones head when olive oil works just as well.