How to resolve upstair leak and water damage in unit?

The condo above my unit has a water leak in the shower valve that has cause damages to my ceiling and dry walls in the closet and master bathroom.

The co-owner leases his property and he has his own management company managing his properties (not the condo management company). I did a little research on my own since I don't have insurance coverage and found out the co-owner lives in the same condo complex. I contacted him directly and showed the damages. He initially agreed to fix the damages to my unit and informed that he would get his manager involved. He also asked not to notify the Association as we could solve this between us.

Several weeks went by and nothing happened. I contacted him again and he basically said it's not his responsibility and he won't repair anything.

I got the condo management company involved and they responded that anything inside my unit is my responsibility and that they won't get involved between co-owners disputes. I have provided videos and pictures about the mold and damaged dry wall and wrote a demand letter requesting to investigate the unit and file a claim with the Association insurance. I have not heard anything since then.

I reviewed the Bylaws and there is a section about Association insurance covers interior walls. I called the Association insurance carriers (there are three carriers) and informed about the damages. They responded back by saying that is has to come from the condo management company.

I wrote again to the management company demanding to speak with the board of directors. Have not heard again and my phone calls are clearly ignored.

What are my options here to solve this in civil way?