As a manager, and also as someone who has done similar herculean efforts, it can be 'dangerous' to reward such efforts because it becomes the norm, you are expected to put in this kind of effort on a regular basis.
My take: if this guy was expected to spend three weeks completely rebuilding the architecture of a core system, then (a) his management layer sucks and he should have quit for that reason alone and I imagine that had more to do with the resulting layoffs later on, (b) retooling a system in three weeks of non-stop effort, even with minimal sleep is about 300-350 hours of work -- even spread out that's about 8-10 weeks of "regular" effort, which as a 20yr vet in the industry, doesn't sound like that complex of a system.
The Social Security Administration publishes numbers[1], although they are arguably somewhat lower than the actual COLA changes.
Six months later: review time. My boss tells me that he was monumentally impressed with the dedication, perseverance, and capability I demonstrated throughout the year, especially on the aforementioned product. And, as a result, he was very proud to give me...a 3% raise. I was deeply offended, and that was the beginning of the end for me there. I quit a few months later. I hear that layoffs have been rampant since I departed, which makes me feel a little better.
Anyway, long story short: fuck those guys. Polish your resume and tell them you're doing it.