Sick Betta

hello! a have a very sick betta splendes. he has some kind of fungus theat eats him alive. the top lip has been eated by this fungus and from his belly comes out the same white fungus that is on his mouth and eyes. he's active, but he can't eat cause the fungus is in his mouth. what shoud i do? i have some photos with him. please help him!

As its in the mouth its probably columnaris.
You will need a bacterial med and aquarium salt to help get rid.
What is the temperature of the tank he is in and can you give more info on his environment, such as tank mates, size of tank, filtration, water stats, water changes etc.