Hegh doesn't mean be dead; it means die. To say He's dead now, you need to indicate the dying is complete. Heghpu' means died as in having completed dying. You probably don't want DaH Heghpu', because that suggests he undertakes and completes the action of dying NOW. What you probably want is just Heghpu' He died, he has died, with the now understood, or maybe DaH yInbe' He's not alive now.
Thanks for the tips; I'm still very early on in the course, and have yet to learn a lot of this. Sometimes the best way to learn is to try, make mistakes, and be corrected. :-)
So the suffix -pu' can be an indication of aspect (or completion), as well as being a pluralizing suffix?
Yes. -pu' on a noun means plural beings capable of using language. -pu' on a verb means completed, or perfective, aspect. There's another perfective aspect, -ta', which means the same thing as -pu', except it carries the connotation of having set out to accomplish the action. -pu' can always be used whether the action was intentional or not.