I'd say he's ambidextrous with a slight preference to his left hand. I'm like that, but my parents didn't realize it for a long time. We thought I was right handed until I was 11, and it was causing problems. I switched to my left hand, and they cleared up! But because of that, I do most other things with my right. Eat, play sports, etc. I draw with either, but can't brush my teeth with my left to save my life!
Because of that, we've done a lot of research about the sides of the brain and side preferences. Not only do you have a hand preference, but a foot, ear and eye preference. Watch what foot he starts walking with. Watch what eye he closes if he needs to focus with one eye on something, the eye he keeps open is his preferred eye. Also what ear he turns towards sound, like listening through a door. Most people are a mix, and these other preferences don't mean anything for what hand he uses, it's just interesting. I'm right footed, but everything else is left.
Whatever you do, don't pressure him to use one or the other. Even if he never really shows a stronger preference for one hand over the other, let him write with whatever hand he wants. I wouldn't assume eating with his left is mirroring who he sits across from unless you've seen him watching what they do and trying to copy. I'd say he mostly eats with his left.
Ambidextrous people really have the best of both worlds, they get the "advantages" of being a lefty but can manage using right handed things. He sounds very adaptable!
4 in 5 years, what were we thinking? July 07, April 09, Nov 10, and August 12