Hello Peacedove, feedback can frequently be given but any negative thinking patterns can have a strong and sometimes devastating effect on our relationships, health, work or ourselves, but with experience it's possible to be free from these thoughts.
People try distractions, or ‘drowning their sorrows’ only to beat themselves up for still
being stuck in their negativity, but it doesn’t fix the problem it only prolongs it.
As your son becomes negative then there are a couple of ways, this might not work for some people, but you have to keep experimenting to each time he is, because his mood may change or it maybe something else completely differently to the last time.
Putting your feelings into words may benefit or when he can see the bigger picture, it helps us for feedback in its proper perspective, then he can decide how to respond.
We may not always see him the way he sees himself and when we hear something new, it’s usually a good idea to ask a few questions whether he would have noticed we had seen this before.
When he has these negative thoughts the problem is he believes these thoughts are true.
He needs to recognise his unhelpful thinking, but with this you have to be careful the way you say it to him and ease off if you need to.