Dynamic Content Filtering is an HTML5 feature for responsive layouts as it relies on code not available in WebHelp. Instead for WebHelp you can use Content Categories (sometimes referred to as Dynamic User-Centric Content) to provide end-users with various options in a dropdown. The content is then filtered according to their choice.
The author can customize the content according to user roles, product types, geographical areas or whatever is preferred.
In this sample project the WebHelp Content Categories output is set up to show how this works. Generate that output and you can see the differences.