you can also put the hummus on toast or tahini on toast, I think a tablespoon of tahini is equivalent to one cup of broccoli/bok choy. Unfortunately, Kai is not on very high sals yet so haven't got up to this bit yet.
You can buy canned red salmon, the bones are mashable, I make patties with potato and fry them. I personally hate tinned sardines so don't serve them much
I also steam a whole lot of bok choy and broccoli, blend it up and mix with sweet potato - baked and chopped also an egg yolk and butter. They need to eat with an essential fatty acid and egg yolk to absorb all the vitamins including calcium. He will easily get half a cup into them that way.
Another way to get it into them is to add the blended broccoli and bok choy to a GF and dairy free waffle mixture and make bokchoy waffles in the waffle maker. I usually make these every second day.
Oh I nearly forgot. I also make homemade chicken stock once a week from an organic chicken. I don't have any figures on it, but I know alot calcium comes out of the bones and also into the gelatinous stuff, so I mostly cook his meals with the homemade chicken stock. Hoefully that adds to the total too!
I figure of every meal has something high in calcium in it, then that's the best I can do.
He does get about a table spoon of buffalo yoghurt a day too. I guess it all adds up
Also, its not on the lists, but egg yolk is high in calcium and vitamin D, and essential cholesterol, so keep adding to cooked veg.