Bad split ends can anyone help?

i have really fine hair and i have alwys had a problem with dry and split ends. The ends of my hair are always so split and dry and whenever i brush my hair it goes frizzy. I know you're not meant to brush your hair that often but my hair tangles really fast so i have to... I haven't straigtened my hair for about 9months because im letting it grow out so i dont know why i have so many split ends. I let it dry natrually all the time and I always wear it up! I also deep moisturiser it but that doesn't seem to work, and I have also been using coconut oil, which also doesn't work what can I do to stop it looking so dry and gross?