It’s a tricky one. I love this question because I’ve been in this boat before, but with family.
I can perhaps share what a good, and now late friend of mine used to do as she was the local ‘agony aunt’ for many close female friends. Maybe that will help?
She would listen and empathize about a certain topic. Let’s say it was about the car. Then she would help the person to find alternative ways of dealing with life without the car, but allow the person to come up with the suggestions themselves.
After that, the car was then off topic. She made it clear that the person had already solved that problem and was not going to discuss it again.
If it was an errant boyfriend, my friend would listen and then do the same thing. If the caller called again to complain about their boyfriend that topic was out of bounds.
My friend, Elaine, had counselor training but more than that the had a good heart, but firm boundaries. She understood where she began and another ended. She didn’t sympathize but empathized, there is a difference. She didn’t allow her feelings to go into a downward spiral simply because someone else was down.
She also was selective when she would answer the phone. Meaning if her own energy was low, she would just allow it to go to voicemail.
She’d also tell the person midway that ‘They have had their turn to chat, now it is her turn’. Teaching them that there were TWO people in the conversation. I really respected Elaine, I love her for her kindness, but boy oh boy you certainly understood her boundaries, which she would place in a kindly way. I hope this helps?