Can one trustee be removed from the trust without informing the surviving spouse?

This depends entirely on the structure, wording and authority granted in the trust, which I assume is a living trust?

What role does the surviving spouse play? Does the trust address his/her authority?

I scanned this article but don't see where it says they are required to be informed of the action. It may be a function of whether informing is written into the guidelines of the trust. This may be a question for an attorney for the state in which the spouse resides.

https://www.legalzoom.com/articles/how-to-remove-a-trustee-from-a-family-trust