Just taking his wreaks and doing the repairs for him gratis is not such a great idea and the exception to that is if you are doing the repairs for hire thats OK but an entirely different arraingement.

What is a great idea for both you and him if you are both open to it is for you both to spend time in your shop (not his because you will find it difficult to work in some elses shop). There you can demonstrate various methods and ways to approach various repairs and he can practice with your supervision. You can cover anything from major repairs or simple monocoat practice to just setting up controls properly, something often poorly done.

This is the most effective way possible to 'Pass it on' and I practice it almost every day with someone following me home from the field. You will find this quite rewarding and most folks are very greatfull for the help.

John