Dry hairs are result of seborrhea. This will result in increase dandruff on your skull. Avoid dandruff and completely remove hairs by razor. The new hairs will come soft. To keep them soft, use egg + yogurt on skull.
How Can I Put Moisture Back Into My Hair. It's Really Dry?
Look for hair moisturizing Conditioners, they have the emergency kits for really damaged hair, and for every kind of hair. I use a mixture of Infusium 23 and water in my spray bottle for wetting my curly perm because I have dead straight hair. I also use good leave in moisturizers right after a process. 
Pour coffee and water mixed together in your hair
This might sound gross, put a little bit of mayo in your hair or you can also use coconut milk.