Jesus wept do not use horse shampoo on your hair, have you ever felt horse hair?!?! Not soft at all xD
I really struggled with thick coarse frizzy splitty hair that half arsed waved and half didn't and greased at the fringe and roots and had a scalp plagued with psoriasis.
So i cleaned up my diet, focused on getting all of my minerals and vitamins (tablets didn't do much) in what i ate and plenty of healthy fats and protein.
I then cut off all the damage i already had and stopped using heat. COMPLETELY. Embraced what i had (which got a lot lovelier once I stopped destroying it).
Finally I stopped shampooing. Yup. I figured I clean my face using cotton wool and moisteriser, and my skin is soft so why not my hair? So I use conditioner, you can water it down if you need to get it all over without using loads, but I really massage it in, really well, to lift the excess oil and flakes out (this encourages blood to your scalp too which is good and its a nice little massage) and then rinse really well in cool water, you might need to do it twice, but your hair will feel clean i promise! I then use a richer conditioner on my lengths as these are very dry. It can take a few days for your skin to calm down and not produce lots of oil, so give it chance to adjust.
I have a wide tooth comb to detangle (gently from the bottom, no dragging or tugging) and a natural bristle brush that I use to move oil from the top to the lengths where it's needed.
It's never been so soft, my stupid frizzy wave kinks are soft defined curls and I love it. I have minimal flakiness on my scalp and I get compliments.
My 2 pennies :)
Please back away from the horse shampoo xD