I understand you're chronically newfag because you joined yesterday but do not fucking do this. If you or anyone else actually finds anything, archive the hell out of it, share your findings, and don't pozload my neghole. If you find something clearly illegal properly report it significantly before you share information publicly so the pos does not start panicking before investigation.
Family, 9 times out of 10, do not care or will ignore some retarded stranger contacting them to tell them their beloved son/brother/whatever is being a degenerate— They have no reason to believe a stranger, especially one sperging (albeit rightfully) how despicable someone they love is. It also leads to them DFE and locking social media, consistently no matter what.
Family will not implement consequences. They will cope and pretend the reality of the person they love being terrible isn't real because it doesn't actively affect how they live. Look to Tim Win and similar cases to see how well "contacting the family" has worked. It's inevitable they will be contacted by retards trying to play autistic vigilante once information is public, but don't be one of those retards and shoot everything down beforehand.