I got the one tier version of this one for Christmas and I love it! It was really good quality despite the cheap price. The one tier one is OOS atm, but this one looks just the same yet can hold more rings! I love it because it fits in my small bathroom sink drawer no problem.
Take him to a jeweler to get properly sized. Or you can buy a ring sizer: https://www.localeclectic.com/products/perfect-fit-ring-sizer https://www.amazon.com/esLife-Measuring-Reusable-Finger-Jewelry/dp/B0B12QWH1M
>Does anybody know where I can get similar rings to the ones Wanda Maximoff wore in the beginning of Civil War? Or at least tell me what type of rings they are? (The ones on her ring finger on the right hand)
https://www.amazon.com/dp/B0922HW576 this ring is similar to what you looking for.
I did some searching and even tried an image lookup but did not find anything EXACTLY like your ring. However, I did find the best results when I searched for cherry rhinestone rings, so you might want to keep searching in that direction. For instance, I found this similarly styled apple ring and cherry keychain. I hope this helps a bit!