A friend has a Mudbuddy 7000 (short transom) with a 35hp Vanguard. Motor is locked up and does not work. Wiring was cut to separate from motor. He's trying to find out what is the value on the whole unit as it sits today? Sell the whole thing as-is, or part it out?

He'd probably get more for parting it out since it is locked up.
The frame should still be good.
And there are bolt on mods that should still good.

What year is it? Here is something to think of as a starting point. If the motor could be rebuilt you might be able to ask more.

I'll tell you in 2015 I paid 3,000 for a 2013 GTR frame that needed nothing, was in great condition, and had a good prop. The only thing I put on it was the actual motor.

3,000 was about the most I'd pay for a frame in good shape. If you put a 2,500 dollar motor on it you are up to 5,500. Any higher and people may start looking at new units.