Should i put my dog to sleep?

Ever since getting hit on the head by a car he has has frequent seizures usually 1 or more a day. He dosn't have the hop in his step as he used to and he is even beging to loose his teeth from crashing into things and biting wood from the pain. He only has 1 k9 left and really nothing else up in the front. The seizures themself also look very painful when he screams and looks really confused when coming out of one. I love him, I really do, but its getting difficult for me to manage (constant cleaning poo and musus off him) so it mest up for me to say but its the truth but it is getting annoying and he is falling apart. I even cought him hanging from his back leg from my window shades ones. He must have been their for hours and judging by the looks of everything around him it looked like he has a seizure, ran into the window, got caught up and just got stuck their. Their was blood all over the place took him down and bathed him fixed up the cuts.