Try getting him to divide the evening duties a bit.
Have your 10yo set out their clothing and school stuff for the next day, and then have them sit with your 3yo while you set out the clothing and school stuff for the 5yo and clothing for the 3yo. You can have your 5yo come with you which will give you the opportunity to start showing them what they need to set out so they can learn to do it themselves.
Have your DH do the bedtimes for the younger two, while you and 10yo do the washing up, quick tidying up (toys, etc), and packing lunches for the next day. It gives your DH some 1 on 1 time with each child, he can read them each a story, etc.
That gives you a bit more time in the evening.
My DH does the bedtimes for our 5yo and 2yo every evening. We each take turns cooking the tea in the evening, and whoever is not cooking is with the children, attempting to tidy up the living room and running the vacuum around it if needed.
DH works in the very early mornings until the afternoon, so morning stuff is pretty much mine by default.
On weekends, all duties are shared, although he still does bedtimes, as that is routine.
I definitely think your two older children can be helping out, but then so can your DH. A 10yo can easily be helping with washing up, folding clothes, sweeping, vacuuming, dusting, and sorting their own room (making bed, putting away clothing, and such). A 5yo can help with setting the table, putting away their clothing (with some general instruction), helping to make their bed. I'm sure there's more you can come up with, depending on what needs to be done.
DH is fully aware that the only reason he is able to work at his job is because I am taking care of the children and the household at home while he is gone.