I’m not sure 2 trips to Ibiza & continually on the sesh would go down well with any HR! If they sacked him he wouldn’t have a legAs long as you have a doctors note, you can do what you like (within reason). A company can't question you or comment on your your activities while you are off, if they have concerns they can send you to one of their doctors.
And of course Sean is getting illness benefit , but that would just about cover his take away bill!