Got new info today. My only choice may be to delay distribution til AS is 55.
If I want to put addiction-related restrictions on distributions, I will have to designate a real human being as trustee, not the trust department of the financial services company as I had planned. I talked to their trust department today and they said they wouldn't do it.
AndreaB, about the annuity idea--when the annuitant dies, that's it, right? Whether or not all the money has been distributed? My AS is in his late 20s. If I die in the next few years (hoping not!), 20 years of the magic of compound interest means there would be a LOT of money in that trust by the time he's 55. Almost certainly he would live to get only a fraction.
And a lump sum distribution even at 55 does not seem to me to be a good idea.
Still thinking through the possibilities . . . .