Hi, Kalikorose,
The Apple Support resource you found your way to the Apple Support Communities from, If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support, is the best place to start when there are audio issues on your iPhone.
If the issues are exclusive to the videos your daughter-in-law sends, we would suggest verifying with her if the video has audio on her end. Some devices allow you to mute video audio during or after recording. In those instances, it would be expected that you as the receiver would get a video with no sound.
If she does have sound on the videos, we would recommend making sure your volume is all the way up:Adjust the volume on iPhone - Apple Support. Then, follow the steps below if you still need some help:
- Close any open apps: Close an app on your iPhone or iPod touch - Apple Support and restart your iPhone: Restart your iPhone - Apple Support. Some times this can help clear out an issue that's arisen while the phone has been running.
- Make sure the iPhone is running the latest version of the iOS software, iOS 15.4: Update your iPhone, iPad, or iPod touch - Apple Support. The latest software will ensure your iPhone has all the latest security features and other important features and settings.
- Check for, and install, any available carrier settings updates: Update your carrier settings on your iPhone or iPad - Apple Support. Since messages between you and an Android user are sent using your carrier's network, updates from them may help resolve issues sending and receiving.
Best!