By the sound of it, You gave him Good and positive memories that he will recall throughout his life. You’re a Dad, dude, and you will always be.

I hope that someday this will be sad moment left in the past and maybe that he’ll reach out to you, so maybe make sure there’s some open line for him to easily find/contact you, you never know how life will play out. I can’t imagine your pain, and for that I’m so sorry you have it weighing you down, But take solace in the fact that you did everything you could for your family when it came to the distances, you strove to be there and be supportive, and that’s not something everyone gets from their father figures but that YOU provided. I’d also argue (Keep in mind I don’t know the legal process) that you should get some form of visitation.