There are more members here in the UK than in the USA (take a look at the member map).
There are a number of people who remanufacture parts and have become specialists in specific machines.
Personally as my hobby I supply the majority of Ransomes MG spares.
Please do not take this as a critisism of your thoughts but the problems of what you suggest are many fold.
CNC machines (Computer Numerically Controlled) are very expensive and take several forms plus specific tooling can seriously add costs.
I have a reliable number of suppliers who do manufacture parts on my behalf when I do not have the facilities but it can take many years before I see any return on investments made.
Establishing precise engineering specifications for parts can take many years of research and may just not have sufficient returns to cover time and costs.
Safety is a paramount concern for some parts and manufacture would probably be avoided by anybody charging for the part.
Many of our parts are very heavy and some owners around the world have to suffer huge carriage costs whch restricts demand.
If your friend has access to specific machines and skills he could off these on the site or VHGMC.
These are only my observations and not trying to put you off trying which I applaud and I wish you good luck and success.