I disagree - sure, his wife doesn’t work 60 hours a week out of the house, but as noted earlier, dealing with little kids constantly is hard work, especially if you’re doing it on your own most of the time. Not only are little kids notoriously whiny, which is really grating, they’re also messy and destructive and keeping a house reasonably clean or at least free of obstructions you might trip over is not at all easy. Plus, there are some mind-numblingly redundant, boring tasks involved that you have to do over and over and over - putting on clothes, shoes, diapers, trying to understand the garbled sentences, helping them communicate, repeating yourself over and over and over to provide clear instruction and teach them what certain things mean, picking up toys (and instructing your toddler to pick up toys) that you’ve already picked up five times before. Then there’s cooking all the meals and cleanup after all the meals and other household maintenance.
I don’t think it’s at all unreasonable if she’s in the process of cooking dinner with a toddler clinging to her leg (to whom she’s probably responding by getting him juice, talking to him, giving him a snack, etc.) to expect her husband to get up long enough to get himself a book.
That said, it’s also her responsibility to tell him if she’s too busy. And she should do so in a way that’s calm and reasonable, not just say yes until she gets asked one too many times and explodes. There’s a world of difference between, “I’ve got my hands full - can you do that?” and “Goddamn it! Can’t you do anything for yourself?”
It also makes sense that she should do more of the housework and childcare since she’s physically present more; however, I’d say if she’s as busy as it sounds like she is, they’re equally deserving of a break and maybe could benefit a lot from some improved communication.