Mrs. Chase married an immigrant from Czechoslovakia, Rowan Chase. She was also an alcoholic.
Chase's mother locked him in the Rowan's study when she couldn't take care of him. Rowan left the family when Robert was in his early teens, which gave Robert no other option but to care alone for his alcoholic mother until her death, at least five years later which was approximately ten years before Season 1. Dealing with his mother helped him empathize with Luke Palmeiro, another teenager who was trying to deal with a parent who couldn’t care for themselves.
She eventually died.