Richard left, and Helen Bruch.
Richard and Helen Burch are Timmy's parents. They first appear in "Timmy 2000", being comforted by Phil Collins.
Like their son, they can only say their own names, they have large heads, and they use wheelchairs. Presumably they suffer from the same syndrome that he has.
Their family portrait shows the three of them sitting on their wheelchairs in front of the Eiffel Tower. The picture allows us to presume they have some means of consistent income. Their house is green with a gas tank next to it.