Don't be embarrassed! The quality of individual clubs can vary a lot anyway. Show up and see how it is.

What do you recommend, outside of dropping money on the ARRL manual, to help me get back to being able to participate again?

There are plenty of free things out there. The ARRL manuals and license class manuals are overkill.

Try Youtube videos. Dave Casler has many good videos and some series aimed at building up knowledge from the ground up.

I just want to be able to program my radio and understand repeaters again.

You can ask someone to help with that. People help each other all the time with this, no matter how experienced they are.

Using Repeaters is relatively easy though, but programming your radio depends on the radio. Some are much easier than others.

I haven't used it much since then. I had a medical issue that has robbed me of long-term memory, but not intelligence or learning.

I have a neurological disorder too, but it affects my short term and working memory. Part of my motivation for getting licensed (all the way to Extra) was to see if I could. If the test were not written though, I wouldn't have been able to pass.