Yes. Say don't worry honey, you will get it. Keep trying. These things take time. I love you now go have fun..................
For challenges in life in general because I think your son is rather young. The only thing you should be helping him get is patience and persistence. Leave the gymnastics to the coach.
Take him back to what was hard and or what took time. With video.
See when you were a baby, you couldn't crawl or walk. Then you you could crawl but you still couldn't walk.
See you couldn't talk as a baby, watch all you could do was babble. See how you called cookie, guh guh............
Math is another good one if old enough. Whats 4+2. 6 my kid would say with her oh mom eye roll. Yes you got that really quick, remember when you had to use your fingers.
For my girl when she got frustrated I would show her videos of her very ugly first cartwheels and attempts at splits.............. See it takes time and lots of practice.
Now when she claims to s*ck at something, I just look at her and hmmmm how do you get better.. And I get I know, I know, practice (with eye roll). Me, yep you'll get it, when you get it.
Your job is have the conversations you want him to have with himself. Work hard, give it time, listen to your coach, you'll get it.