Poison ivy ol (urushiol) is active for a whole YEAR on "dead" roots and stems. I use a product called Iva-Rest but never got it as bad as your husband. I had loads of the stuff in my yard when I bought my house and am constantly battling it.

Ortho Brush-B-Gone actually will kill poison ivy down to the root. It is one of the very few herbicides that will even touch it. I've heard bleach works, but rinses off too easily.

Hubby should get himself to the doctor before it gets worse.