Fell Papyrus's P.O.V:
It started like any other day. Get up at 5 a.m., make breakfast and get ready for a day of hard training. Everything was going well until I heard very harsh coughing coming from my brother's room and then the sound of him teleporting to the bathroom and shutting the door.
Shortly after the sound of throwing up was heard as well as ragged breathing so I went upstairs and knocked on the bathroom door a bit harsher then I meant to which made my brother make a sound similar to a yelp. Before I even said anything Sans responded with "I'm ok boss I will be out soon."
I knew that sans got sick often so I didn't question it too much but, its getting more frequent and honestly very concerning. Suddenly there was a very loud slam of the front door which was followed by a very loud yell that could only belong to Captain Undyne. I greeted her as we usually do with a sparring session and then offered her favorite drink when we were done which she accepted.
While she was distracted I went back upstairs to find sans laying in his room which looked like a proper room instead of a vacant storage unit. There was brown carpeting, a bed, a red wood dresser and lights instead of dim candles. what caused the change was because of a incident a few months ago.