Does a person bear the sin of encouraging the viewing of a TV series if the sin of watching it transforms from a minor to a major one?

Yes, whoever guides another to a sin incurs the same sin as the doer, without diminishing anything from the latter's sin, whether the sin is minor or major; because he is the cause. This is confirmed by the Almighty's saying: (That they may bear their burdens in full on the Day of Resurrection, and some of the burdens of those whom they mislead without knowledge. Unquestionably, evil is that which they bear), and the Prophet, peace and blessings be upon him, said: "And whoever introduces a bad practice in Islam, and it is acted upon after him, he will have written upon him a sin similar to the sin of whoever acts upon it, without diminishing anything from their sins."

Watching lewd movies and TV series can be a major sin even without repetition, because it combines looking with lust and excitement, and listening to forbidden music. They are designed to arouse instincts and destroy values, which makes persisting in them dangerous. Guiding others to them is considered a major sin.

The path to salvation from these sins is sincere repentance and enjoining good upon those who were invited to this evil.