Who's got the power?

[KayeJen]

Our Dad just recently revised his Will with a provision as follows: Dad bequeaths entire estate to trustees of the trust designated in the "Mom & Dad Family Trust," between "Mom" and "Dad" as Settlors and as trustees, and as amended between "Mom" and "Dad" as Settlors and "Dad" and "Son John," as trustees, to be administered as provided in that trust agreement, including any amendments made to it before his (Dad's) death. Based on this, Son John believes he now has the authority (as a co-trustee) to amend/change the structure of the "Mom & Dad Family Trust"--either on his own or in concert with Dad. Further, Mom has already given Dad her POA as to her fiancial affairs. Only in the event of Dad's incapacity (not happened yet), Dad has given his POA to Son John--in which case then Son John will be sole trustee. Son John also believes that as sole trustee, under these eventualities, he will have authoriety to amend/change the structure of the "Mom & Dad Family Trust." Is Son John correct in his interpretation of his authority--or is he misunderstanding the reach of his authority and thereby misunderstanding his fiduciary duties and discretionary powers? (Upon the death of both Mom and Dad, Son John is also 1 of 3 sibling beneficiaries named in the "Mom & Dad Family Trust." Thanks for help and insights.