Here is what I am reading: "Dear Annie, My sister's house is burning down. How do I get her to stop blaring her radio at night?"

Look, I say this as a chronic overtipper (I've been known to tip over 50% on super-small checks - like $8 for breakfast - because I figure I am taking a table which could have been earning the server server could be making serious bank if it were seating four instead of just me): tipping is really, really not the issue, here. The issue is your sister's mental health. That should be your focus, here.