PADI certification is permanent; however, I got my Advanced Open Water in 1999, and haven’t dived since.
The refresher course is TOTALLY online, with one day of pool work, and the course is very basic and intuitive. In ‘99, we had to use dive tables. Everything is computerized and (allegedly) idiot-proof now. Call your local dive shop.
LOL, my PADI open water license is so old that they cannot verify it by number. I do have that and my Y cards to prove I am certified but they challenge the ID of the young woman in the photo until I point out the cert date . I have taken a couple of quick in pool refreshers but, truthfully, I am no longer a strong enough swimmer to do much more than snorkel.