No blog/cms. No Drupal.

Actually Drupal feels ancient and archaic at this point. I wouldn't recommend it for anything.

If it was strictly a blog I would use Wordpress.

Plus using a framework like Drupal or even Wordpress you're opening yourself up to lots of security issues.

For any type of web application beyond a blog that is PHP based I would recommend going with Laravel.

Not only is it a great framework there are lots of tools to make it easy to use.

Develop locally on Homestead (Vagrant) http://laravel.com/docs/5.1/homestead

Deploy easily to Digital Ocean or AWS ($10/mo but will save your hours and hours of time) https://forge.laravel.com/

Critical App?Deploy with no downtime https://envoyer.io/

Laravel Spark (SaaS out of the box, Coming Soon) https://www.youtube.com/watch?v=uOU_N8PNOD8

Laracasts http://laracasts.com Great place to learn Laravel.

At least checkout Laravel before committing to doing this project in Drupal.

I would charge 3x if he insists on Drupal. = 0

Good luck with your project.

(btw, I'm just a fan of Laravel.)