Two issues - Mobile rendering and sublink

Unfortunately, there is no easy way to disable responsive layout for this theme. That’s how responsive website should appear on mobile and not zoomed or scalled.

Maybe you can try this solution that I posted a while ago. However, I have no guarantee that it will work for all mobile devices.

To fix dropdown or so called submenu you can add this code to your Child Theme style.css or inside Appearance >> Theme Options >> Other >> Custom CSS.

#main-nav ul li ul {
  top: 37px;
}

Let me know if this helps.