If the account is a uniform trust for minors account the money is the son's not the trustee's (Jane/Mom). There is however an issue with who is trustee for Son Doe.
This is not legal advice nor intended to create an attorney-client relationship. The information provided here is informational in nature only. This attorney may not be licensed in the jurisdiction which you have a question about so the answer could be only general in nature.
It makes sense to work with an Estate Planning attorney in that jurisdiction. Use the 'Find-A-Lawyer' search engine above at the top of this page. Good Luck on this one.