Obligatory you under terms of service cannot share accounts.
If it is the launcher you are sharing it does not matter who has what, the account will only access what it has paid for.
I would not advise letting a friend log into your account. Should anything ever go amiss, there will be a record of you sharing your account, and thus a reason for the CS Team to decline assisting, should they decide to.
It is, of course, completely against the EULA you agreed to.
Not affiliated with ArenaNet or NCSOFT. No support is provided.
All assets, page layout, visual style belong to ArenaNet and are used solely to replicate the original design and preserve the original look and feel.
Contact /u/e-scrape-artist on reddit if you encounter a bug.