Once upon a time, I was a dedicated BlackBerry user myself, and didn't think that I'd be able to adapt to a virtual keyboard due to peripheral neuropathy in my hands. However, it was a touchscreen BlackBerry that made the change possible, using haptic feedback through the keyboard.
That tiny "zt" the keys make as I press them reassures me that an entry was made, and quickly got me past the need for a physical keyboard. Transition to the multifaceted SwiftKey keyboard cemented the shift, and I'm 9½ years past BlackBerry now. That keyboard brings facets like Word Substitution, built-in language translator, clipboard, Tasks, and other things that eliminated my hankering for those features that I did miss from BlackBerry. SwiftKey's engine powered the BlackBerry virtual keyboard, and is really easy to work with. He can also adjust the size or the keyboard, and the key press duration for faster or slower typing if needed.
But the reality is, I really thing BlackBerry is like the jobs in Bruce Springsteen's "My Hometown," "they're going, and they ain't coming back." The once mighty BlackBerry ceded power to Apple and Android, like Windows phones did, and will become a curiosity more and more, much like regular flip phones are.
Besides, I think your boss will be surprised how far beyond smartphones have evolved. Numerous Android phones have had keyboards in the past, but they have never really been real popular, nothing more than a niche in sales, and I don't figure you'll see many in the future.