There's no available spice model for AD8567. I suggest you can use the AD8565 spice model as a replacement for AD8567 for simulation purposes since both have the same specs and they only differ in the number of channels inside the chip. AD8565…
I think Matt is on to something, but the AD8567 is a quad. Look at the AD8542. It's a cheap dual that should get
within 20-30 mV of ground sinking 100 uA. See figure 22 on the AD8542 datasheet.