You can see in the very first line: width="942"
That is going to prevent it from shrinking lower than that. But even using a Table with two columns in the first place is going to be a problem because you won't have room for the left nav and content to show up on the page on mobile even if it does shrink.
The solution is going to be to lay it out with DIV tags and move the left nav into the hidden menu for mobile so that the content can be shown properly but the nav can still be accessible when needed.
That is why I want to do a training session with you to explain the concepts and get one working right for you.