Melbourne

No worries, I hope it helps him keep his hand in without overwhelming him. They look expensive at Officeworks but a bit cheaper on Thrift Books. Perhaps you can find some old ones on Ebay, or free legal PDFs? Perhaps by getting past papers from tutoring sites or some such. I googled 'naplan books pdf free legal' and saw stuff like that but I'm not sure which are legit. There's also 'free study material for homeschooling australia' to try.

If all else fails there used to be Educational™️ computer games. When I was little they used to be things like Math Blaster or Lost Secret Of The Rainforest but surely there's something more modern.

Also seriously work together with the school and see if you can get some leeway on this (if you haven't already) because unless he's attending or being homeschooled there could be strife. Even if Mr P is feeling really unwell he could rest on the couch while Eldest works his way through something, and Eldest can get a reward for each completed page. (The reward heavily depends on his age.)

But even if Mr P can do that much definitely access social workers and/or respite care in any way you can, whether it be through the council, Human Services, or Peter Mac. Perhaps see if one of Miniest's friends can sometimes have her over for sleepovers to give you and her a break. You're going through some heavy stuff and nobody is meant to do this much alone.

You might also be eligible for help at home