Express scripts/evernorth enguide

My son has a new job that offers Express scripts as the PBM. I am trying to understand his coverage in regard to GLP-1s (specifically Zep but at this point Wegovy would be OK too). When he looked at the formulary, it listed Zep but it didn't specify a PA. When he looked further it said something about needing a PA and that the coverage was only for the card holder! I assume that means his wife is not covered - I've never heard of this, am I interpreting this correctly? It's not even clear to me how much they actually cover. Plus there is this Evernorth Enguide thing that provides a mail order pharmacy for only GLP-1 drugs. What's the deal with this? If anyone has experience with these things, please let me know. I thought I could give them some advice because of my extensive and crazy experience with Caremark but this is even crazier than anything Caremark has done. Yes I will get him to call Express Scripts...