A 13 year old boy in general can eat you out of house and home, even if they do not have ADHD. Ask other moms of boys your sons age and older.
To ban eating when hungry does not make sense. We cannot control their hunger as teenagers.
You just need to make sure you have approved food for these late night snacks. Work with him about what he is allowed. A sandwich, the left overs? But no junk food.. Do not even keep it in the house.
I have known my husband since we were 13. He used to wake up in the middle of the night and eat all of the left overs. Half a pot of stew, A pot of spaghetti, the rest of the meatloaf in half a loaf of bread! A platter of Nachos. I remember his mom being amazed. Keep in mind, he was thin as a rail. He ran track and rode his bike to school .
He does have ADHD and has never taken meds for it. You do realize it is not something he will ever grow out of? As you get older the ADHD and ADD get worse. My husband is an adult with ADHD.
But your sons hunger will eventually taper off.. Usually around 22 years old. But this is typical of young men.
The throwing away silverware? Is that because he thought you would see the dirty silverware in the sink?
Have you actually told him how much each Sterling Silver Spoon costs? Have him call around to different jewelry stores and price the company, the pattern and type of spoon. It will make his head spin.
Could it be a passive aggressive expression against you for your attitude towards him and his late night eating?
Could it be he just is a teen boy and not thinking straight? Is pretty clueless about money and how much things costs? I do not know many men in general who could tell you how much flatware costs.
My husbands mom has always acted very disappointed in my sweet husband. He cannot control the ADHD. He was born this way. My husband has always felt guilty that he was not "Normal" (his own words).. His mother has admitted she had resentment that he could not be "Fixed"..
YOU need to make sure you are getting the therapy and an education about how to help your son, not just punish him.
HE will need tools to figure out to handle his needs.
MY husband has zero sense of time. Through modern technology it has helped him work this out.. Online calendar. Cell phone alarms, Ipad timers.. Strict schedules with times and dates that HE sets up himself..
He has also learned to ask for help. i have learned never to brow beat him for asking, but instead to just help him without comment. I do observe what it seems he needs and to make him aware of my observations without any judgement.