hi there.
parenting is the biggest fear and challenge in the world, methinks.
getting him a job at a bike shop is the BEST idea. of course he's not gonna do cartwheels over having to have a job, but i'd guess that a couple of weeks being surrounded by the things he loves and with people who have excitement, passion, and KNOWLEDGE of bikes is totally gonna give him something to look forward to in his life. that may be the best investment yet.
just a suggestion, but why not try an outline? or talking to him straight up? something like "look. we see you directionless and unmotivated. this concerns us because, typically, this behavior left unattended leads to being lazy, careless, and unhappy. we absolutely believe you are a bright kid who would be happiest being productive...you're too smart to let the brain rot away, and we are sincerely interested in coming together with you to get a plan going. we wonder if you're TEMPORARILY clinically depressed, because we see (list behaviors.) this can make LIVING life really difficult. because we love you and believe in you, we want to help you get this in check, and then we'd really like to sit down WITH you and help you figure out the next step, like getting a job doing something you'd be interested in doing. if we didn't care, we'd let you do whatever you wanted until you did whatever you wanted somewhere else. but that's not the case, so there are two options. ONE: you refuse to be part of a team, and we become NAZI parents and unravel this whole situation, because the current living arrangements simply are not working. OR TWO: all three of us accept this as a challenge we can work together to try to better. it'll require patience, honesty, forgiveness, acceptance, trust, and motivation. it will also NOT be easy, there will be good days and bad days, and all of us will occasionally lose our tempers. but i think you're worth it, and i'm willing to do this as an investment into the person you have yet to become."
he's a kid. but he's an individual. he's lost, but he's got caring people around him. he's not going to trust anyone, so he's going to be difficult, but that's his right as "the kid."
you're the parents. you're a team. you have choices to make: let it lie as it currently is. kick him to the curb. become NAZIs without ears and make him a soldier without a voice. or turn it into the best team approach you can give, stating the reasons why, and then dedicate yourselves to it. kids who have depression, trust issues, and lack of motivation or self-confidence don't really have the option to make it better for themselves because they don't know how and they're not independent. whether he knows it or not, he is relying on y'all to invest in him and have faith in him. lost people end up in the arms of those around them...seems like the people he's going to fall into love him and believe in him. make him aware of this, continuously confirm that you believe in him, and roll up your sleeves.