Roger,
I do hope your friend didn't try to blame his drinking on the massive amount of work he was doing on your car up to the stage he was caught?
Seeing what has been done up to this stage could have caused people to have gone "off the rails" well before this.
But, at least, with all your assisting him, you did learn a thing or two about his trade. Being self-taught by helping is a wonderful accomplishment.
Bruce. 
Don't worry Bruce! My friend was just there to weld and do difficult sheet metal forming; I did the "ugly" work with spot weld drilling, rust removal, adjustment of parts...Furtermore, I was not totally neophyte with metal work: it was part of my apprenticeship more than 40 years ago; shortly after, I worked for 2 years in a body shop. However, without practice, the skills are going away. Usually they come back rather quickly if it's necessary!
By the way, while I was working on the Biarritz, everybody ask me "and after this one, what car will you restore?" my answer was all the time "no more, I have no space anymore!" which is partly true. As I have yet to discover how it's possible to drive more than one car at thesame time, I decided that 3 Cadillacs in the garage was enough. Furthermore, with the age, the floor is lower and lower!
Now, I came back to my first love: model car building. No, no: not the ones you can buy at the store and assemble: doing a car from scratch. Like a difficult restoration, it takes years to finish ONE model. What am I doing now? a reconstruction of a Studebaker Avanti at the scale 1:12. I began 4 years ago, I still have one or 2 years until completed. You want to see samples? OK, 2 pictures as they are not Cadillacs: Olds Toronado (1:12) and one recent picture from the Avanti at work. On the models, you can open the doors, trunk lid, hood, ash trays and so on. The side windows are electric on the Toro, they are manual on the Avanti. Most of the body is made with polyester; frame and chrome parts are made with brass.
I know, I'm mad. I had a bad accident when I was 15 years old: I fell on the head.