Changes to my mother's living trust: Will I be notified if brother cuts me out?

I was the sole executor on my 94 year-old mother's trust when it was drawn up. I have one living sibling who is married, but at the time, my Mother put only my brother as a beneficiary, but excluded my sister-in-law completely.

I suspect that my brother's wife either has - or will - convince my mother to change the trust and take me out completely and put my brother and herself IN as executors. Mother is gullible and easily swayed; she "loves the one she's with" and my sister-in-law knows this. So while I'm at work, she goes to my Mother's house and "helps" her, etc. I can imagine that this SIL offered to drive her to the attorney, and may have even offered to pay for the cost of changing the trust.

If / when the trust changes, do I have the right to know? I will call the attorney who did the trust as a last resort, but he knows us and I would like to guard my privacy until I have the answer to this general question.

Thanks for your reply/replies!