Get a tackling dummy so you can practice at home in comfortable surroundings. I will assume by valid you mean that he was push into hitting and tackling before he knew how to properly do so. This is not something you want a non/less aggressive player to learn on the fly. The fear part will take time, but if you practice proper technique at home on the dummy it will help. 1. the hitting of the dummy and falling to the ground will build toughness. 2. When he learns to tackle properly with out thinking about getting hit by lots of reps on the dummy. One day he will be at practice or in the game and make a perfect tackle and he will win that battle and win his confidence from the congrats he get from his teammates and everyone.

Walk through proper tackling: 1.see the target and square the target up (get the player in front of you) 2. at about 2 feet drop your hips (get low as you can) 3. make contact shoot head to the left then to the right side give them a big hard bear hug (shoot your arms/ wrap them up) as you drive (chop your feet) through the player/target/dummy. Walk through these step then speed it up until you back him up 5 to 10 yards and let him run into the dummy with the proper technique you have taught him. He's going to hit the ground hard a few time like that then you can stand behind the dummy and give as much resistance as you like to get him use to hit bigger stronger players and driving his legs.

you play weplay

get him to tackle you as hard as he can. if you convince him that he can tackle you he wil think he can tackle anything

im wit head hunteer

Talking about nature. This player might be more offensive minded, a thinker. I'm defensive myself. You need to be able to think on both sides. Defense is more react and attack. Offense is more elude and strike. Being a direct part of the scoring process might turn that switch on.

Perhaps your son isn't meant to tackle,but evade tackles. Channel that fear and turn it into a positive. See how successful he is when he is given the ball in game time situations, or simulations. If that doesn't work, then perhaps football isn't the sport for him.

TACKLE HIM!!!!