Not speaking is not automatically unhealthy.
Sometimes silence is what prevents a bad conversation from becoming cruel.
Sometimes a person needs time to think.
Sometimes words are not available yet.
The problem begins when silence stops being space and becomes punishment.
Healthy space has information
Healthy space sounds like:
"I am too upset to talk well right now. I need an hour. I will come back at 8."
The other person may not like the pause.
They still know what is happening.