I have fine hair that loves to split because of that I am a protein queen. I do a light protein Aphogee 1 time a week and then every six weeks I do a heavy Aphogee protein. My hair is never dry or hard, well never say never, but it's not an issue for me.
I co-wash a few times a week. Whenever my hair is getting frizzy and the curls need to be reset. So depending on what I do that week it could be 2-4 times. I always deep condition after protien, even the light 2 minute protien.
I would say, either chop off what is damaged or slowly trim it off and start a good protien regi to prevent further splitting.