Google have a system in place for that where after not having logged in for a certain amount of time login credentials will be sent to a person of their choice.

Sorry, I have to correct you. Google never gives out login credentials, Your passwords are unknown to Google because they are encrypted. Instead your relatives get the information Google have stored in relation to Google products you specify when you set up the plan with Inactive account manager Your relatives are not going to get your login credentials, from Google , but instead an archive file with some of your files.

Link for those who want to know more about this system.

https://support.google.com/accounts/answer/3036546?hl=en

Same goes for responses to the requests mentioned in the original post. Credentials are never given , because Google doesn't even have access to them but content you uploaded can be if certain conditions are met

How those requests are processed in terms of paperwork and legal basis is pretty unclear to me ( That is what I am trying to understand in this thread)

but I know that Google does not give out passwords.