A lot of our clients use MP for Twitter automation, they get password reset every now and then, but that's mostly because too aggressive settings or because Twitter detected bot behavior.
So, you'll have to use settings that will make your account look human
as @mommyfats said, don't use only one or two tools (follow and unfollow), throw in some favorites, a retweet or two per day, some tweets and account should be fine.
Oh, yes, don't forget to add night mode, couple of hours when none of the actions will be executed. Also, ask your client to avoid logging in to that account.