Flash educational content : How to repurpose for mobile/tablet solution?

Last week, we met a customer who wanted to migrate his web content to androids mobiles/tablets. They wanted to transform their interactive books to mobile format. Assuming it is HTML, I asked them for HTML content. There came HTML content with media and interactions done by Flash.  They wanted Flash to work on all tablets. I do know that flash does work in tablets version 3.0 and above. But most of tablets in India are 2.3 and above. How should I proceed?

I find that a lot of learning content today has been designed and developed using Flash and I started to look at  Flash Plugin roadmap. It was a good read and i felt that the platform is transitioning away from content authoring/publishing developers. It seems to make a lot of sense with advent of HTML 5 and Adobe interest to support the same. Also saw the page Adobe guts mobile Flash player strategy

What about the increasing number of mobile devices that we’d like to deliver learning to? We know that the Metro Touch version of IE will not support the Flash plugin.  Given its memory intensive nature, iOS  developers made that choice a long time ago. With content, one wants to be able to develop once and run on both desktop, mobile and ‘in-between’ devices.  I understand that a stable and feature-rich HTML5 development environment is yet arrive in scene to match the depth of Flash. Earlier media rich functionality was developed with Flash and technically intensive content was build with HTML.

What will a web without Flash look like? What would all companies do that have applications or games that are Flash based?  Are we going to see a mass-migration of content and  authoring tools to the HTML5 standard?

My client was not happy with me when I pointed to them that Flash was not supported and they have to think of migration. He pointed me to use Flash as we have shown that it works in our application in the tablet he has selected to push down to students. I became sad as this does not help the end users of the application who are the students.