this is all very theoretical but here is my best guess.

lets call the two observers A and B. and lets assume they are not negatively impacted by the physics of where they are at. if they were on opposite sides of the black hole, they would not be able to see one another as the black hole which is solid would block the view. But lets say the black hole is transparent. In this case you will still see nothing due to the gravity well. If you look towards the center of the black hole, it would be absolute darkness as no photons are able to reach your eyes due to the pull towards the center. if you turned 180 degrees away from the center, you would be blinded by the amount of light coming at you from the event horizon, this will be caused by the inverse gravitational lenseing that would occur on the inner "surface" (not an actual surface but an appox of the event horizon). if you turned 90 degrees to the left or right and look along the perimeter of the event horizon you would see a distorted image of observer B on both sides of you. While the gravity prevents the light from escaping the black hole it does not prevent it from orbiting the black hole like a satellite. so some of the light leaving observer B would travel parallel to the event horizon perhaps perpetually. looking up or down in the same manner would give similar results but, looking up you would see the top of obsever B's head. if you look down you would see observer B's feet. crazy thing is if observer B was not there, you would see images of your self. if you looked to your right you would see the left side of your self. look down and see the bottom of your feet ect.

TLDR: you would not be able to see across the hole as it would be darkness, looking behind you would be blindingly bright, and looking up, down, left, or right you would see 2 distorted fuzzy dim copys of observer B along with everything else that has ever come into this space.