No, she doesn't. She has to act in the best interests of the trust and it's beneficiaries. That may mean doing exactly what you typed and the way the market is right now, doesn't seem too bad to me.
It's not really the best market to be hanging on to securities and it's the best market to sell houses.
Thing is, that doesn't dissolve the trust nor her responsibilities as Trustee.
You can also request your share, as I said before. So tell her you want her to cash out some of the securities and apply your half of that sale to keeping the house that you are in, for fair market value of an appraisal. The Trust turns over deed to your house, in exchange for half the value of it, paid for by the sale of enough securities, reducing your half of said securities held by the trust.
Then figure out what else is owed you from the trust and get that in cash, dissolving the trust.
As for trust duration, you're way out of whack. I am the 4th trustee (as unbiased as it gets) of a 100 year old trust.