This is common sense it remains. A facebook page, weibo page or myspace page they all remain. All you need is the persons password to log on. If the person passes it is like a person's personal belonging they don't get rid of it. I knew a guy that passed his mother found his password and added something to it so all of his friends could remember him. 

All info you input in sites like facebook or weibo are stored in a database forever, so even if relatives have the account closed, the info will still be saved somewhere so it will always theoretically exist and float around cyberspace. That's why, when you delete your facebook and rejoin a few months later, all your previous info and pics are still there.

I don't know about weibo, but for Facebook, immediate family can request the account to be deleted, or they will memorialize the account, settings set only to current friends and the decesed is no longer a "People you may know." Facebook will not give the password to the account to anyone, nor will anyone be able to log in to the account. Only current friends will be allowed to post to the wall to leave memorials.