12mm Pineal cyst with high melatonin levels

1 1/2 years ago my now 10 year old had 2 MRI's with contrast due to early onset puberty and headaches.His bloodwork showed a level 30 melatonin level -I do understand this varies greatly and is hard to pinpoint but the sleep clinic is shut down here now. His hormone levels are above average. He now has headaches 5 out of 7 days, usually morning and night, treated effectively with OTC's. His sleep patterns are very unstable- can't get to or stay asleep, is difficult to awaken. He is frequently nauseated  and his depression is darkening. he sems to have sinus issues consistently.  Last week he had a "march"; shooting pain in 1 arm that lasted through most of the day.  His last MRI has shown a 12mm Pineal cyst and we are seeing an endocrinologist on Monday to get his bloodwork done. We have not seen a neurologist but his file has been reviewed by 2 ; 1 at U of Michigan, 1 at Children's in WI. Both say they will not see him because there is nothing they can do at this time.
We have changed our diets in the hopes of decreasing possible headaches triggers, are trying to get his sleep cycle better with no luck and are doing all we can short of drug therapy for the depression. We are journalling all we can to hopefully find patterns or clues. I have zero confidence in his pediatrician but believe the endocrinologist can help in many ways.
A: is there anything else we can do?
B:is there any facility/physician you can suggest that may have a better handle on this? We will go anywhere-he cannot live his life in pain.
C:Is there any information or specialists regarding melatonin studies? We are looking into Northwestern however the neurologist specializes in adult melatonin studies.
D: What bloodwork should be done? Where would this recommendation come from (in order to help the endocrinologist understand why they would be needed)