What if my gate hinge post is loose?
It sounds like it would be best to replace the hinge post.  The True Latch may still possibly work in this kind of situation.  The brace may still work IF the hinge post is attached to a panel where the next post down the line is sturdy and will not allow the hinge post to lean toward the gate from its own weight.  But the brace will likely NOT work if the hinge post is loose to where it leans toward the weight of the gate.  Then the brace would not be able to make up for the lean of the hinge post.