Is there any way to control the volume button so a blind person doesn't accidentally put the volume down?

If the person is using voice control accessibility to control their phone. They can say the command, “turn down volume” or “turn up volume.” Although these just turn it down or up one increment at a time.

there is a “mute sound” and “unmute sound” command but I think that would just be for media. You can discover all commands by going to settings>accessibility> voice control>commands and then click each option to view different commands and functions.