YAW for assuming every camera software has the same featureset as a flagship product from the most powerful global tech company on the planet but YANW for wanting him to address a concern of yours, and frankly a basic privacy protection for streamers in general.
It is important to confirm if it's the tech solution that is an impediment, or if there's some ulterior issue at hand.
He's probably using OBS (a free and open source program, which typically means very plain functions) which doesn't have a native "blur background" checkbox easy clicked like Google Meets might have.
If he is on Windows, he can try this: https://www.xsplit.com/partners/obs
Or if macOS then maybe this: https://help.manycam.com/knowledge-base/chroma-key/
Otherwise, likely he'll have to:
Make an alpha mask (a cutout) of his head shape, feather the edges with a transparency gradient, in which case he'll mostly have to stay perfectly still for it to work.
Hang a monochrome curtain behind his setup and run third party 3D processing software to chroma key it out. But in that case, he might as well just hang any old curtain without the software part if the goal is to just block the bedroom and not design a customized dynamic background.
Sounds rough. If you can't make the counselor thing happen, I at least suggest you read this book (or one like it) and offer it to him as well: http://www.amazon.com/Nonviolent-Communication-A-Language-Life/dp/1892005034