Well that's it isn't it Kat, rather than worrying about Alexander and Dh's needs, well Dh is an adult. Alexander actually appreciates what you do - a lot! Dh needs to decide some of those things for himself. You keep going strong Kat!
I do agree with Cutestuff too. When you've mentioned some of his not-so-nice reactions, they have been when he is not at his best (trying to sleep, organised things with mates..), and yes it is his fault that he puts himself in that sleep-deprived boat, but timing those conversations about Alexander may give you a better, more rewarding and connecting result? Eg during dinner together or when Alexander is unlikely to need you. I'm also wondering about how he believes parenting works? Is it worth having an appropriately timed conversation (date night?) about that? Did he grow up with a housewife/working husband type of household where his mother tended to all of the kids needs? What role was modelled to him in his home by his father? I ask because he may just have different ideas to yours, rather than he being uncaring?
All the best gal.