Non-dependent adult working from home living with senior citizen parents

I am an adult and am responsible for filing my own taxes, as I provide most of my own support.  However, my son and I live with my senior citizen parents, rent free.  I recently heard that they may be able to claim the fact that I work from home 3 days a week on their taxes, since I am doing so in a room in their home and using their internet.  Since I am not a dependent to them, nor pay rent, is this true?  I would love to help them in any way that I can, since they are helping me so much.