@mothninja This is a huge topic, but as a blind accessibility specialist, I can be of help.
Recommendations in no particular order.
1. First of all, blindness is not an emprisonment sentence. His life will not be easy, — I'm not part of those people promoting blind pride, — but if helped correctly, he will continue living a full, prosperous life. Nothing is ending, he is not doomed. That can be obvious or not obvious, but I really want you and him to understand it firmly.
2. Start now. While he still has eyesight, let him start learning his screen reader. TODAY! (Sorry for yelling, but it's really important and I cannot put text in italics or bold here). Why? Because if now he gets lost, if something is not accessible, he can still look at it and find or ask for a solution.
3. The best screen reader. It's a huge holy war, like Windows vs. Mac vs. Linux, iOS vs. Android, PlayStation vs. XBox, etc., etc. but no matter what, Windows is the easiest and by far the most accessible platform out there. I don't know about your attitude towards that open-source fever of today, but if you really want your father to thrive, it's Windows on PC and iOS on the phone. I recommend JAWS for Windows, the screen reader I've been using for 28 years now. It's kinda expensive, but might be gotten by means of the country aids. However, I don't know his background. If he doesn't do anything super sophisticated, maybe it's worth to begin with NVDA, a free and open-source one. The main particularity of NVDA though is that it basically is a lego: you have quite a simplistic screen reader, but there are many addons (plugins) out there that solve many tasks. JAWS is far more powerful out of the box. But expensive. But powerful out of the box.
4. Accessibility. Not everything is accessible in our world, unfortunately. Tell him that, if something doesn't read, if he can't navigate past this link, the chances are very high it's not him, it's app or website developers who made it inaccessible to the blind.
5. Ask for more, I'm glad to help!