Lots of info and opinions already. There are a lot more choices now than black color for anything and jet fins. Steel 72s probably won't hold up as well in HI as aluminum tanks, unless they are your own personal ones and you take good care of them. With lots more options, you'll get lots more recommendations on what you should do and what to avoid. See what everyone says, check it out, then decide for yourself what works best for you
If your husband is just doing his OW class now, consider taking it with him. You will get a lot more insights into what he's saying, thinking, and how he got to where he is than just taking a refresher separate from him.
Wetsuit technology, dive computer technology, lighting technology, regulator, mask and fin materials are way better than 10 or 20 years ago. Buoyancy control devices are all over the place, I'm personally a backplate fan. The biggest difference is physically going from your 40s or 50s to your 60s kind of sucks, in terms of strength, flexibility, and dexterity. Knowing dive tables to plan dives is good, but I'd rather focus on my dive and have my Shearwater keep track of my remaining bottom time. You probably want a computer that allows you to control how conservative or aggressive a no-decompression dive you can do