Skating tips for 7 year old

[Jackson]

Hi, I was wondering if anybody could help me correct a bad habit My 7years son has been skating without bending his legs any further than a hockey stance, and I feel like it really slows him down and is making it harder for him. If that made no sense to you, imagine the letter V, upside down, and rocking from left to right. That is what his skating looks like. It's like he is lifting his feet instead of really pushing l. He finally just started using both of his feet to push like 6 weeks ago. I just can't figure out how to correct it.