Here is what you can do for you buddy. Have a elevator company come out and look at the unit. Give you a proposal on what it would take to get it running. Then get a second opinion from another lift company. Once you have that info bring it too this board. There is a ton of knowledge that exists here. And we can help you in the decision making on what to do next. Asking for that type of advice is welcomed here. Also since that lift is vital to his business he should look into a full service contract that covers it any time it goes down, and you will get a tech ever so often come to perform preventive maintenance. Those contracts cover most things and on a single dumbwaiter it will be less expensive then losing business due to the lift not running. So let us know what the lift company says that needs to be done, we can let you what we think from our years of experience in the field. In the end your friend will find a elevator company who can satisfy his needs and make his life easier.