Okay, now I can see the picture!
Actually, that mole looks very similiar to the one I have on my own toe, and I think it's in the same place but on the opposite foot! Mine developed after my melanoma, which really freaked me out, but my dermatologist has looked at it repeatedly and has stated it is simply a mole. Your husband's may be as well. However, a doctor's opinion is always best.
Moles on the feet/toes are not in and of themselves dangerous, but melanoma in those locations can be. The reason being, there isn't a lot of "meat" in that location of the body. The same holds true for fingers. Normally, if one has melanoma on a toe or finger, excision requires an amputation of that extremity. That can be much more devastating than the chunk of skin I had removed from my knee and the 3" scar I'm living with. Also, because fingers and toes are so close together, it can be tougher to isolate a single area, and the chance of melanoma spreading is greater. It is much easier to isolate melanoma and remove all the cells when a doctor is dealing with a "meatier" part of the body, such as a leg, an arm, or the torso. (I know my verbal description is probably not all that delicate, and I apologize for that!)
Melanoma in and of itself is fairly rare, so take comfort there. This mole on your husband's toe is probably just a mole. Your husband can insist on a biopsy if his doctor doesn't do one, but biopsies on toes (and fingers) can be tricky sometimes, as well, because there isn't much skin.
Good luck - you're doing the right thing!