I would leave out the references to your other family members, and to SSA. VA will already know that you are SSDI/SSA, its part of what we look up. The references to your family may be useful if they were discovery for court, but VA disability is about you, and only you. if it didn't happen to you or wasn't experienced by you, it didn't happen. I would simplify your support statement down to the bare minimum of What you have for a service connection event and any treatment in service or complaint in service, something that shows you have a current disability now, and then briefly explain how you think they are related. Posting studies about things that you weren't directly involved with (like medical trials, for example) doesn't do much for you because the studies aren't about 'you', they are cross-section of other people. VA, for good or ill, is only concerned about you- its like the MST claims I work on- you may have a personal trauma event/PTSD or similar because of something you witnessed, but for MST specifically if you saw something happen to someone ELSE its not an MST based claim, because MST by definition has to be experienced by you.
Bronco pretty much covered the rest.