My wife is dying. She is in hospice. They told me to do a division of assets what does that mean?

Who is "they" who told you this?

It means move enough assets into your own name so that you won't be strapped for cash when she dies and her assets get tied up in probate. Money in joint accounts should be ok in most cases.

I would think this is tricky so may need a lawyer.

My parents wills were always what's mine is yours.

My Sis and BIL had to do this in ILL. to get Sis into a SNF that took care of patients with ALS. With the financial separation of assets Sis qualified for Medicaid. She has been in the same facility for over twelve years now. BIL passed away about ten years ago and that did not effect Sis's care. It helped protect his income and the house, etc.
In their case it required an attorney. Find an attorney certified in Elder Care and talk this over with the attorney.