Hmmm....A lot of suggestions...Which are correct, and which ones maybe not so much???? I don't have the exact answer here..
My two cents, when it comes to teaching youngsters the value of work...Is it goal orientated? Paying some kid, or anyone for that matter, time on the job...I wouldn't....It's goal oriented...When the job gets done, this is your reward...In this case money.
Is it for the parents to pay? I say no...They worked for you, not the parents. The rules are...You do this, and I will pay you for it. I can't pay you until the work is completed. Allow the person to make choices. Try not to make them for him.
A little tid bit interjected here. When I was much younger, working on a farm, I was assigned to rake hay with the tractor. I was trying so careful to rake it over just right. But it wasn't just right.. The farmer told me, "Out here, we have to work, or we don't eat"...I never forgot his words, even to this day.
On another post by Palidin (sp) He and his wife had to deal with the situation, similar to yours...It's admirable for your trying to help out this kid with problems...BUT......As you are well aware, with your mules...some you can lead them to water, but you can't make them drink it.
Give encouragement..."Kid, you want to be better than some of those other kids you hang out with" ? "Here's how you can do it"....Let him know, that you and others will look up to him for being a good worker, a good, talker, good manners, what ever.....Find out what the kid is interested in. What are his goals and ambitions. Make allowances that this is a 15 year old kid...Some boys became a man at age 8, some boys never did.
(I used to teach flying, I had to find something in common for my students and flying. I had to relate to what their background was, and what they wanted out of becoming a pilot...What could I do to to help them achieve their goal) (I had a Doctor who was always late, or wouldn't even show up sometimes, without letting me know.) I had to say eventually, I was willing to teach, but he had to be willing learn, to do his part too.....By showing up on time, like he expected his patients to do. If not, then we would have to part ways.
But if it turns out after more than a day, that he is in fact "lame". Well...realize he is not you.
There's two things working here, with and against that kid....You and his mother....To me, you sort of have to work with the both of them...That can be a very challenging proposition. What exactly does the mother want you to do with/for her son? Let the mother know what you can or can't do with him...What you will try to do.....
Anyway, I've jabbered on long enough for my two cents here.
Best wishes,
WuzzFuzz