Schaub has thrown six touchdowns to start the campaign but has also recorded four costly interceptions, including one that was run back for a defensive score in his side's defeat to the Baltimore Ravens last week.
Cushing told USA Today: "Matt's our leader, our quarterback. And we know he's going to play better. There's no question about it.
"This whole organisation has trust in him that he can get it done. Obviously, when you lose, people are going to look at the quarterback.
"It's the glamour position. And if we're not putting up 30, 40 points, everyone asks, 'What's wrong with him?' Matt is in a lull right now. But in one day, he can be right back firing on all cylinders with our offense."
The Texans face the San Diego Chargers on Sunday.