What do i tell my son when the father told me to tell him he was dead and wanted nothing to do with him?

Tell him his father turned out to be bad person and that you're sorry you picked such a loser to have him with. But explain that most men are good people who don't abandon their children and that your intent is to raise him to one of those. It helps to have a good uncle, grandfather or male friend to provide the masculine influence he'll need.

It's a case of the white lie. You can't tell him daddy hates him, bc he will internalise that as being his fault.

Maybe talk to him about loss and how like a pet, we have things we love, but sometimes they don't love us back, or have to be rehoused (obedience or behavioural issues) and how some people can be like that as well. Reiterate how much you love him, but that daddy doesn't love himself enough to love (your son) so you have to shine your light, anyways - I as your mother will always be here for you.

Not the best example, but a start. Also, avoid dumping your frustrations with his father, on your son. Children are able to sense emotions very easily, and they soak it up like a sponge. Do your best to avoid that much-adored blame game - i.e. putting down his dad in front of him. If you must, be with a few trusted friends and let off steam that way.

Lastly, thousands of solo mothers have made great men out of their 'father abandoned' sons. You can be one of them.

i wouldnt say anything

I have a hard time believing this is true. But if it were true, i wouldn't tell a child that ever.

Yes, it is better than being deceived by having a bad father

That depends a lot on what kind of relationship your son and your ex have had up until now. Assuming your son is pretty young there is absolutely no reason to tell your son that his dad doesn't want anything to do with him.