Nice thoughts on helping your friend, giving someone a leg up when they are down is very rewarding.
I have a friend in UK who is now extremely wealthy , he runs a specialist engineering company with four employees making specialist fabrications for high value gas and oil projects as well as one off prototypes for all sorts of people, all his work is gained by repeat business and word of mouth commendations. Your friend needs to find a niche market which requires high value one off or low volume machining/fabrication projects. The markets he needs to look at are oil and gas /mining, automotive restoration of rare high value vehicle parts , steam engines etc. The other area where people spend a lot of money is on one off architectural metalwork , creating wrought iron gates ,lighting fixtures, room screens etc. I know that Jay Lenno has a huge car collection with an attached restoration workshop where they can actually reproduce more or less any rare or obsolete part for any of the cars and vehicles they have using CNC and 3d printing machines. People will pay huge amounts of money for bespoke iron work such as gates , setting up to manufacture such things is not expensive and can be developed slowly by producing small samples and items that are not too expensive and taking them to rural shows architectural exhibitions etc. If it was me I would try and get a low cost foot in the market to test potential before I spent big money on machines, if you gain a specialist commission that needs a machine you can very quickly buy one. As a final thought it may be worth making contact with a number of one make car clubs such as Ford V8 owners or Bugatti , Bentley owners clubs and asking them if there are any specific parts which they have difficulty obtaining, as an example I know that V8 flathead Ford exhaust manifolds are very hard to find .
I hope that is helpful and wish you and your friend good luck.