Welcome to the FRF and sorry for your loss.
Let me start with the simple stuff.
2008 was the first model year for the 3120DS. It came on a Ford V10 chassis or a Chevy V8 chassis. Depending on what you want to do with it, either one will work.
They are worth about $25,000 - $30,000 if in very good condition.
Now the hard part. It’s a 10+ year old unit. Everything is out dated. Other than chassis parts, if anything is needed it will be challenging. If you are up to the challenge and can do things yourself, it might be doable but if you have to pay someone to do everything you will be pouring money into the proverbial hole.
Next consideration is the lack of use this unit has had. That can be as bad as abuse. If it was not stored correctly, trouble looms. 23 hrs on the genset may be very bad.
So what do you know about this unit? What year and make is the chassis. The VIN will tell you that. What does the title read?
Still interested? or maybe alternatives?