I know that there is sperm in seminal fluid, but how much?

400 million. During ejaculation about 400 million sperm are released in the man has a normal sperm count. There are about 5 million sperm in preejaculatory fluid which is why the pullout method is not advised.
Need a semen analysi. Every man has a differnt count, but he can get a semen anaysis by an infert specialist, don't send him to a regular lab , reg lab is not as good as going to an infert specialist.