Cull it, save yourself the time trouble and stress, and relieve the bird.
I was in a very similiar situation this past winter but worse.... I had one kill the other (I think) to this dsy I'm not sure what happened but I remember a dead quail and alota blood I never examined him properly but I just disposed of him.... then theres was another quail half of his head was bone I could clearly see his skull... and he had 1 eye gone...I tried to get him better he started getting better first two days but then got much worse very skinny wouldn't eat or anything.... so I ended up shooting him with my pellet rifle (I couldn't let myself do it any other way with a pellet rifle its just pulling a trigger much easier). As far as "Big Bertha she'll do fine I've had birds live out well with one eye.
I was in a very similiar situation this past winter but worse.... I had one kill the other (I think) to this dsy I'm not sure what happened but I remember a dead quail and alota blood I never examined him properly but I just disposed of him.... then theres was another quail half of his head was bone I could clearly see his skull... and he had 1 eye gone...I tried to get him better he started getting better first two days but then got much worse very skinny wouldn't eat or anything.... so I ended up shooting him with my pellet rifle (I couldn't let myself do it any other way with a pellet rifle its just pulling a trigger much easier). As far as "Big Bertha she'll do fine I've had birds live out well with one eye.