Q: Can the Exsultet be accompanied to assist a deacon who has difficulty singing it a cappella?
A: There’s no rule against it. GIRM 313 permits the use of the organ to support singing during Lent. That would logically extend to the Exsultet.
The idea is to make it a confident, joyful proclamation—even though it strikes fear into the heart of many who accept the task.