Roberta Jarvis, a physiotherapist who treated Louise Clifford after she was diagnosed with the disease at the age of six, said she never saw the public relations guru act inappropriately with women.
Mr Clifford, 70, is on trial at Southwark Crown Court, London, accused of 11 counts of indecent assault against seven girls and women - all of which he denies.
Ms Jarvis, who worked at the Canadian Red Cross Memorial Hospital in Maidenhead, said Clifford was "very concerned" about his daughter's therapy for arthritis, which she suffered in most of her joints.
She told the court: "He was a parent of a single child. This was his daughter.
"He wanted absolutely the best for her.
"He was always very concerned about what was going on, how she was being treated and asking for information.
"He was very caring. Very charming. A perfect gentleman as far as I was concerned and very helpful when it came to fund-raising."
The court heard Clifford helped raise £300,000 for a new hydrotherapy pool after services were moved to Wexham Park hospital in Slough.
Asked by Richard Horwell, QC, defending Clifford, if she ever saw Clifford act inappropriately with women, Ms Jarvis replied: "No."
The trial continues.