Did your consultant offer any evidence that hypnotherapy had no effect on tremor?
I don't know whether hypnotherapy reduces tremor, but I suspect that it might have a small benefit for little cost or effort.
Stress certainly makes my tremor worse. Hypnotherapy can reduce stress. There might also be a link to the placebo effect (see the latest Parkinson's UK's research newsletter).
This is one to research and test on yourself.