I’m extremely pleased with the battery life on my MBP. In addition to the super hardware and software, my minimalist approach to apps seems to pay dividends in battery life. I’ve been using the MBP non-stop since 5:30 this morning; it is now 1:15pm and I have 56% battery left.
This is probably due to the apps that are running and what work is being done. I have a minimum of apps running and most of them are native, which are very efficient. Additionally, most of my work is text and web-based. I open other needed apps and then close them when finished, e.g., DEVONthink, Pages, Numbers/Excel, etc.
Agree with @Bmosbacker — you would probably be around 45% after the same amount of time elapsed, with his apps. If you were finishing work in time for late dinner, you’d be just fine. He can make it until after his bedtime, assuming he’s not too much of a machine to need sleep.