Yes, you are responsible for your guest’s behaviour. As the ticket purchaser, you must ensure that your guest understands and complies with the Ticket Terms of Use and the Stadium Code of Conduct. If FIFA Ticketing determines that a guest has violated these terms, their ticket and potentially all tickets purchased by you, may be cancelled without notice.
The above-mentioned documents can be accessed in the relevant legal section of the tournament, available through FIFA.com/tickets.