Where I work, depending on exactly how it was phrased, that would be a genuine, earnest, proactive hint from manager that a) They've noticed that you are not performing at your norm and b) They want to understand your circumstances, tactfully, and help & support.
How an employee responds to that depends on many factors: The relationship employee and manager have, the trust between them, the motivation on employee side to be open and honest and look at mutually-beneficial alternatives, remain in that team/company, etc. It also depends on culture of the company, and hugely on just the person - what they want and how they want to approach it.
Not knowing any of those factors, I cannot suggest how you or your partner should approach it; however, how I would approach it, and how I hope my team members approach it is:
1. Be as open as comfortable, as detailed as productive about:
a) What you feel is your impacted performance, e.g. "I don't feel I'm creating code to my standard of quality" or "I've noticed it's become difficult for me to concentrate in afternoon meetings" or whatever it may be
b) Circumstances / causes you may be of that. Again, personal comfort and relationship/trust are a factor. I would feel comfortable talking to my manager "My newborn is keeping me up at night, and the 7am daily standup puts me between rock and hard place", or "My A/C is not working and I'm finding it hard to mentally focus when my office is 30C", all the way to something as longterm as "I don't mind remote work on daily or weekly basis, but i've noticed over last 12 months that I've lost some subtle motivation, internal vision of the goal and camaraderie" (fwiw, I've discussed these three with my manager last 6 months). Your relationship may be more formal/distant however, so you may be more comfortable being more generic or abstract. Note managers are highly constrained in HR and rules WHAT they can ask you; that doesn't mean they don't want to know/support - it just means burden is on you to volunteer that information. Here, e.g. Manager CAN NOT ask you if you have a medical problem and what it is; but you are allowed to volunteer it (NOTE: this is specific to my province in my country; check your local religation) and they are then allowed to support you with it.
2. Come prepared, if possible, with proposals and compromises. It's awesome if you come to manager not just with problem, but possible solution
"Would it be possible for me to skip 7am daily standup, to ensure I am rested and productive rest of the day?"
"I think I might be more productive on QA then on development for next few months as it would motivate me and engage different part of my brain"
"I cannot maintain the tempo of operations in the long term, but I think my ops experience could really make me a productive release manager / developer / whatever to support this team"
etc etc etc
3. Be positive, open, non-confrontational. Explore possibilities together. Give their proposals a chance; sleep on them if that's what it takes to remove initial negative gut-reaction.
How an employee responds to that depends on many factors: The relationship employee and manager have, the trust between them, the motivation on employee side to be open and honest and look at mutually-beneficial alternatives, remain in that team/company, etc. It also depends on culture of the company, and hugely on just the person - what they want and how they want to approach it.
Not knowing any of those factors, I cannot suggest how you or your partner should approach it; however, how I would approach it, and how I hope my team members approach it is:
1. Be as open as comfortable, as detailed as productive about:
a) What you feel is your impacted performance, e.g. "I don't feel I'm creating code to my standard of quality" or "I've noticed it's become difficult for me to concentrate in afternoon meetings" or whatever it may be
b) Circumstances / causes you may be of that. Again, personal comfort and relationship/trust are a factor. I would feel comfortable talking to my manager "My newborn is keeping me up at night, and the 7am daily standup puts me between rock and hard place", or "My A/C is not working and I'm finding it hard to mentally focus when my office is 30C", all the way to something as longterm as "I don't mind remote work on daily or weekly basis, but i've noticed over last 12 months that I've lost some subtle motivation, internal vision of the goal and camaraderie" (fwiw, I've discussed these three with my manager last 6 months). Your relationship may be more formal/distant however, so you may be more comfortable being more generic or abstract. Note managers are highly constrained in HR and rules WHAT they can ask you; that doesn't mean they don't want to know/support - it just means burden is on you to volunteer that information. Here, e.g. Manager CAN NOT ask you if you have a medical problem and what it is; but you are allowed to volunteer it (NOTE: this is specific to my province in my country; check your local religation) and they are then allowed to support you with it.
2. Come prepared, if possible, with proposals and compromises. It's awesome if you come to manager not just with problem, but possible solution
"Would it be possible for me to skip 7am daily standup, to ensure I am rested and productive rest of the day?"
"I think I might be more productive on QA then on development for next few months as it would motivate me and engage different part of my brain"
"I cannot maintain the tempo of operations in the long term, but I think my ops experience could really make me a productive release manager / developer / whatever to support this team"
etc etc etc
3. Be positive, open, non-confrontational. Explore possibilities together. Give their proposals a chance; sleep on them if that's what it takes to remove initial negative gut-reaction.
... Hope this helps a bit, and good luck! :)