Overspent on what?
Lets be rational.
He lives in a car so he doesn't need heavy duty cleaning supplies and coffee? He has a coffee pot? No. Nor is coffee a need. So buying cups of coffee all day to stay awake because he has no life is wasting your money. He can go to a food pantry or shelter for meals. He doesn't want to? Get a job.
He doesn't need gas in his car. Walking is at least good excerise. Sitting in a car eating potato chips is not. If he smokes, that's a big chunk of unhealthy change too. And its far from necessary. I am not being self righteous. My Kay smokes then complains about being broke. But she no longer buys these things because of us.
You are wasting $80 every three days because you are addicted to your son and the lifestyle you created for yourself around him. Like he is your alcohol and you are an alcoholic that knows she should quit but doesn't want to do the hard physical and emotional work to do it. So you stay addicted. As does he. Both your lives go nowhere. How do I know? This was me and my husband, addicted to Kay.
I have the insight, but nothing more. I am sorry. The only way I know how to help you quit is to not do or say anything. So I probably wont anymore and let you do it yourself. Or not do it. I can only control myself.it took us a decade to break the Kay addiction and it almost killed us.
I will pray to give you the strength. That is what I finally did regarding Kay. Honestly, my husband and I are doing really well since we stopped the craziness. It still hurts my heart, but its not debilitating. We can both function and enjoy our lives and other loved ones. We are no longer letting Kay hold us emotionally hostage. Be well.