Can't we pay taxes for our inactive friends D; ?
ask them Username and Password and get permission to access after u can Pay Tax....

You could, but the hypothetical problem with that is, they may log in again, mass rule break on your account and get you banned, even if they do too.
Hypothetically speaking, you'd be unbanned. However, an example could be that the person with your account details may sell and throw away all your stuff and then IV Leadership would need to help you get everything back, and it can be a hassle, so be very careful when doing such stuff, keep these details in mind.
Regards