Suggest Alternate Medication For Breathlessness While On Keytruda.

My mother is 74 she beat cancer in her throat . She was just a few days of being cancer free. They found 2 small spots in her right lung lobe. We took chemo for awhile but she is now on Kaytruda . She takes this one hour every 3 weeks instead of chemo every week. But her main problem is she has trouble catching her breath if she sits and real still it will go away . This does not happen all the time but happens a lot . She takes zanaxea 3 times a day(1) and buspirone 15 mg. Her doctor told me to give her 1 and half withheld zanaxea and see if that helps . At first I thought that it might work but like I said some times it is better and sometimes bad. I really need some help for her. Please help me if you can. Thank you so much, Debra Hester