OK I know you will all probably say no to this suggestion, but hear me out. Very elderly cat came in last night after being attacked, he was only out for 10 minutes, goes into garden and then comes straight back in. I cleaned the area where there was blood , around his cheek. Wrapped him up warm and sat and stroked him. After about half an hour he wandered up stairs, staggered would be a better description and went to his usual spot under DD's bed. He is still there, still alive. I cannot get him to a vets until Monday evening due to working.
I do have a vial of gentamicin and the means to give him a dose SC, I am worried about him developing a wound infection. However I am also concerned that the gent could damage his kidneys , he is 19 so they are probably not in the best of shape although his last lot of bloods were ok ( for a 17yr old cat).