Wikisimpsons - The Simpsons Wiki
Marge Simpson once 'adopted' Nelson because his mother was neglecting him. Sometime after this, Nelson's father returned and the family reunited, with Mrs. Muntz having acquired a job portraying Lady Macbeth in the play Macbeth, after sleeping with the player's director. However, this was shortlived, when Mrs. Muntz began a relationship with Moe Szyslak, and then married a clown.
Mrs. Muntz seemed more caring to Nelson upon an accident following an unauthorized school trip hosted by Springfield Elementary School's then-Superintendent Chalmers, when she hired a lawyer to sue Springfield Elementary.
Behind the Laughter