hell, he'll

Hell or hell means the place where the dead abide, or where those who were wicked while they lived go when they die --
He's making a film full of visions of hell and the afterlife.
Many people still believe in a hell inhabited by demons and the evil dead.

He'll or he'll is a contraction ( short, informal form ) of "he will", meaning a male ( he ) is going to ( will ) --
He'll be there tomorrow at noon.
Do you think he'll agree to the plan?

Now that you know that, you can say--
"He's afraid that if he enjoys life on Earth, he'll go to hell when he dies."