How to Stop a Child from Screaming for No Reason?
«Do you know how to stop a child from screaming for no reason? My wife and I are at our wit’s ends with him.«

I don’t know the age of your child but the best advice I can give you is to ignore the screaming. If every time he screams your wife and you reward it by paying attention to him, giving him what he wants, or even making a fuss about it, you are rewarding the behaviour. Behaviours that are rewarded will be repeated.
You may also try to whenever he screams, tell him in a calm but firm voice: “Do not scream, it is not nice”. You then continue doing whatever you were doing, without paying him more attention. Doing this every time he screams may make him stop.
You can also identify when it is that he usually screams: is it when he is bored? Or tired? You can try to be proactive and distract him before he screams.
I hope this information helps. I wish you all the very best.
Love,
Ana