Under past MA laws Teddy Kennedy would have been allowed to pick a successor to finish out the remainder of his term if he couldn't.
He wants his wife (22 years his junior) to take the seat.
"...State rules that allowed the governor to pick a temporary replacement were changed in 2004 when John Kerry was the presidential nominee and the Democratic state legislature feared then-GOP Gov. Mitt Romney would appoint a fellow Republican if Kerry won..." (source)
They can't change it back now. Sorry Teddy.