Toyota Repair: 2000 Sienna Toyota Siezed up ?, sludge problem, changing oil

Question
Being the only owner and changing oil and filter every 2000 miles or less, since the Sienna 2000 had a sludge problem, I took extra measures to care for it at the dealership.  At 100,000 miles it ran out of warranty and at 102,000 miles it continued to run fine, until ONE MORNING when it wouldn't turn over.Since it was a cold FEB. morning,AAA came by to charge my battery, but once charged, the engine wouldn't turn over but cranked loudly. AAA said it might be the starter or worse.They said TURN IT OFF! It has been sitting 2 years as hubby says he will fix it but he doesn't know what is wrong so does nothing. I need my van to move our daughter 1500 miles, and don't know what to tell the mechanic what is wrong. When this happened I had been traveling to my job that was located in trailers until it could be built; therefore on "construction roads of ruts" at less than 5-10 miles per hour for a time period of 4 months. I suspected a bolt fell off but to date, hubby would not let me get it fixed by a mechanic, yet it is obvious he has no intention of messing with it. I'm sure everything is frozen up and bolts, etc. won't turn. Battery of course is gone so my only recourse is a mechanic or sell it for salvage?  Why would it work fine for years, and no indicator lights or sounds from the engine to indicate problems, and no blue exhause smoke....it just stopped turning over that morning.  Thank you for your kindness in helping those of us who are stumped.

Answer
When the AAA guy was there to jump start it, did the engine start and make a lot of noise or did the engine not start up at all just make noise when trying to start it, it sounds like it must have started because they told you to "turn it off" please clarify? Is there a way a new battery can be installed then let me know what happens after that? At his time there is not information to determine whether the engine is seized or there is something else going on.