Edit: NOTE, I am the receiver of the texts.
So many people asking me to have my wife do something different on her end.
Beloved, she is on iPhone because she doesn’t want to do anything “weird.” She is texting from her phone number using her texting app. That’s what’s going to happen.
Now, why can’t I get iMessage on my android phone? If it’s just a messenger app why not make it available for Android?
I’d use it.
I think everyone has explained the how and why, but not any real solutions that don’t involve using a completely different application. I don’t have an iPhone in front of me, but with Android you can share as a link to Google Photos instead of sending the picture/video directly. I am pretty sure you can do something similar with iCloud. Have her try the share as iCloud link instead.
Update: I just tested it. I had them open up Photos, go to the image/video, tap the share button, and then if you scroll down a tiny bit there is a share as iCloud link. I was able to view it just fine on my Android phone.