That must be a hard situation for you to be dealing with.

Do you think DS's dad might agree to receive some short, written updates about his son a few times a year, with some photos? If you made it clear there was no obligation, he may come around to the idea of having more contact in the future. I guess at the very least, you could try and make sure you are always able to contact him, and he you, in case of medical conditions, if nothing else.

The child support would be helpful to you if you're on your own I expect, but could cause bad feelings that might come back to your DS later. I really can't offer much advice, not being in the same situation, but I'm sure there are lots of single mums here that can help more.

Hope everything works out positively for you.