Parkinson's Disease and Dropped Head Syndrome

My 85-year old father has PD, diagnosed approximately 2004. Early this year he lost his ability to hold his head up. The onset of this condition was rapid, 2-3 weeks. We have since learned that this is known as Dropped Head Syndrome and is most common in ALS patients, but is known to occur in PD patients. Dad had been taking Mirapex, but his neurologist decided to wean him off it, as he thinks there may be a connection. Dad continues to take Stalevo (200mg 4x/day). We don't expect any improvement to the neck from not taking Mirapex - perhaps it will lessen the severity of the DHS?Dad was considering having surgery to fuse C3-C7 vertebrae, however, his neurologist advised against it, as the condition of DHS would not be cured; rather, the "drop" would occur below the fused area.Dad has both hard and soft neck braces but they really don't provide much help. His chin slips inside the brace so his head continues to drop. Tightening the brace makes it very uncomfortable for him.What is your experience with patients with PD and DHS? What treatment(s) can you recommend? Any advice would be greatly appreciated!