He was raised Southern Baptist. His wife was raised Church of Christ. From the content of their messages, I’d suggest that neither adhere to the traditional theology of either group.
Is he a heretic?
Heretics are defined by those with whom affiliation is claimed. Furthermore, it applies only when there are disagreements on “the essentials”.
I don’t really know too much about Gnosticism
Gnostics come from a position of “I Know”, not “I Believe”.
[quotes] but do you think you could compare the Prosperity Gospel to Gnosticism?
The Prosperity Gospel is concerned with attaining material things.
Gnosticism is concerned with spiritual attainment. From a Gnostic POV, the material world is a thing to be discarded.