If people are always martyrs, does it become their fault at a certain point?

This has nothing to do with anyone on Fluther, but someone on another site is always overwhelmed. She is the victim of her family members and always having more work to do than she can handle. She just wrote about being away for a weekend break and getting a call from her sister with MI, a FIL and a brother. At what point should martyrs be establishing firm boundaries? Or am I too unsympathetic?