Re: in case of death; mandatory bitcoin deathswitch Dead man's switch
More importantly, how to do it without rely on 3rd party?
Not easily that's for sure. Although, I get it not everyone cares about relying on a third partyI would say improbable rather than "Not easily". If 3rd party is involved, it's far easier since they either custodial service or act as the oracle on the blockchain.
Biometric chip implant that is set to send the data to a node the moment your vital signs stop for more than x?
Chip malfunctions, all your coins are gone, sorry! 
As long as the data is intact (whether it's private key or signed transaction), theoretically you could regain access to your coin.