I wonder if your friend might appreciate these resources too:

1. Info from Mayo Clinic
https://www.mayoclinic.org/departments-centers/young-onset-parkinsons-disease-clinic/overview/ovc-20529123
2. This PBS film which features real Parkinson's patients as well as Dr. Rodolfo Savica, Mayo Clinic physician who specializes in young onset of PD.
https://www.pbs.org/video/the-only-day-we-have-qtwu1l/
.
I found the film awe-inspiring. Movement is key. There are several programs that others like @hopeful33250 can tell you about like Boxing with PD, Singing, Dancing and more to connect people and keep the active.

Is your friend currently active? Do you do activities together that include getting out and moving?