[quote=“jdsmith”]Is TKD more about throwing?
I like throwing as opposed to striking.[/quote]
No. To keep it (over)simplified, TKD is chiefly about kicking, with a very minor amount of punching. Karate is about 2/3 hand techniques and 1/3 kicking, or 50/50 depending on your teacher. Judo is chiefly grappling (from a standing position) and throwing. Aikido is the most non-violent of the bunch, emphasizing moving in fluid and circular ways to channel your attacker’s energy in ways that deflect his attack and lead to his own tumble, etc. There can be differences in the above descriptions depending on sub-style, teacher, etc. My karate teacher, for example, put more kicks in our training than traditional karate, and also blended in significant amounts of judo, boxing, and practical self-defense moves. But it was still fundamentally karate.
All styles are good. Each has its own strengths. Most practitioners, I imagine, will be biased toward what they themselves have studied. I know I am; I feel karate under a teacher like mine is a more balanced, and practical style than many.
If you study only kicking, and you’re in a situation where kicking won’t work, you’re handicapped. Same goes for throwing. And aikido is fantastic, but the skills, timing etc. are very difficult to learn quickly, whereas blocks and punches can be put to use more rapidly (although the effectiveness of those techniques continues to increase over time).
When taught properly, any of these styles should teach balance, movement, and so on, which will transfer well to other styles. I feel this is particularly true of aikido, judo, and shorinryu karate, but also true of other arts.
Above all, choosing a teacher with the right attitudes (not a commercial emphasis; teaching for the right reasons; valuing the practicality of the art, but also emphasizing humility and peacefulness) is far more important than which style you choose. Sit on the sidelines for a few classes. See if the teacher is making the students recite an arrogant, nationalistic-sounding pledge at the beginning of class (I saw that once at a Univ. of Ill. TKD club, and was very turned off). And so on.
I think your idea is great. Definitely enroll him. Keep it up if he likes it. Switch him to a different class and/or style later if he doesn’t like the first one. I wish my folks had done that when I was 6!!!