The first thing that Henry did was ensure Layla's safety. And the first thing that Dean did was immediately try to oppose it.
Henry called for Emmett and Paul to both come to the apartment, along with three other wolves. They would all five stand watch over Layla while Henry went and tried to hunt him down. They were meant to guard her day and night.
Layla had absolutely no objection to any of Henry's plans, she had no desire to modify it in even the slightest way. In a very desperate situation, she would try and fight an Alpha wolf, and there might even be the smallest chance that she would win.
But the first rule of a fight with an Alpha that her father had taught was that she should try to avoid it as best as she could.
Paul and Emmett were both Betas, but the other three wolves that Henry had called were all Alphas. And there were just much better odds for those five wolves to fight against David than there were for her.