....and welcome to the forum!
I'm sorry about this pain your husband is experiencing.
I was curious to know where they put the battery unit? You mention he has this pain in his abdomen and I'm wondering if it's the IPG unit causing this pain.
Have the Drs gave you any explanation why they kept him for those 4 days? Perhaps they were concerned about a fever or possible infection.
I know how frustrating this must be.

I hope you can get some clear answers very soon.
Make sure the docs are aware that he still has this high level of pain.

Please keep us posted!!

Rae