op's initial point is meant exactly for the people who are having the issues the second person said. you do not say anything about "so that i don't relapse," ever, for any reason. you say simply "i was recovering from a health issue/illness/injury" and you leave it at that. you do not talk at all about what kind of illness, you do not say anything about where you are in the process, you do not get specific at all, you say that you spent that time recovering from an illness.
if they try to weasel answers out of you by asking whether you're able to perform the job duties, you drag it back round to interviewspeak - "absolutely, i am so excited to be here and apply for this opportunity. [literally job duty from the description] is one of my passions/talents/areas of expertise, and i think this would be a great place for me to learn even more."
if they really press, you just say, "i'm sorry, that's a bit personal, but i'm really glad i'm able to work now, and i'm excited to see how i can provide/sharpen/hone xyz talent at this company" or whatever." you stay as nonspecific as you can, and you do not fall for any friendly questions, EVEN IF THEY USE WOKE SPEAK and make you think they're Not Like Other Employers.