Haley was the closest thing to a friend Dr. Zimmerman had. Some time prior to 2376, Zimmerman was attending an important symposium on Vulcan when Haley's holographic matrix began to fail. Zimmerman canceled his lecture and returned immediately to Jupiter Station to repair it.
Haley also worked for him while he designed the first Emergency Medical Hologram. She remembered how proud he was that his creation would be saving lives throughout the quadrant; he even modeled it after himself, which she understood as he'd put so much of himself into the program.
While serving as his secretary at Jupiter Station, she also served as a personal assistant, and prepared his meals. When he came down with a degenerative virus, she insisted that he eat more salad because it was healthy, and made it several times, despite his request for pork chops.
When Zimmerman was convinced that he would die of the virus, he dictated in his will a request that Haley's program be allowed to run for as long as Jupiter Station remained in service.
She also had a working friendship with Reginald Barclay, who was an acquaintance of Zimmerman's. Barclay had served on Jupiter Station while the EMH was being designed. Barclay also occasionally told her stories of his adventures on the Enterprise, and about his friends there, including Counselor Deanna Troi and her love of chocolate.
In 2376, Reginald Barclay brought aboard a holo-program of USS Voyager's EMH, The Doctor. When Lewis altered The Doctor's tricorder to think that he was a Vulcan marsupial, Haley told him that he must like him, as Zimmerman only played tricks on people he liked. When The Doctor's holomatrix began to apparently fail – actually a "glitch" designed by Barclay and the others to encourage The Doctor and Zimmerman to work together – Haley encouraged Zimmerman to work with The Doctor by reminding him of the time he'd cancelled a symposium just to help her, forcing him to acknowledge that he was fond of The Doctor in his own way.
In his last will and testament, Dr. Zimmerman requested of Starfleet that they not terminate Haley after his death. They should let her run as long as the research facility existed. (VOY: "Life Line")