It is allowed to submit an artwork created by your relatives as long as its original and not plagiarized. But I agree its in our conscience if we will submit a commission art and then keep it secret to the real artist, because if you're honest you'll let them know what its all about. On the other side, its a bit risky to ask someone to create an artwork for you. Come to think of it, you'll pay him/her for the the artwork so you can have an entry, but there's no guarantee if that artwork will be chosen as a winner right? In the part of of an artist, regardless of if you win or lose in the contest, he/she is already paid even he/she is not aware of the purpose of the artwork you asked him/her to do.
I think I gave him the information he needs to know. I also inform him that Roobet is a crypto gambling site, I sent him the link to the site so he can check the platform and visualize it. He was aware that it was an artwork contest of a company with a dedicated theme. He made an original handmade drawings, that is his skill. So I never made a secret with him, he also knows about this forum. I never paid him so he can make me an entry. I let him make his own decision if he wants to make it, he knows that winning is no guarantee cause there are also talented joining. I gave him money as an appreciation gift because I'm amazed by his drawing skill.