A conflict of interest means competing or adversarial interests, a dn you haven't provided any details that would indicate any conflict of interest. Here, since this financial advisor is himself one of the beneficiaries, or married to one, it's hard to see how he has any conflict. It seems he has the same interest as his wife and her parents - to grow the portfolio.
You don't specify any time frames, but EVERYONE has lost momey in the stock market in the last few years.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.