I'm just a collector, and speaking only about the stamps and postal cards for Japan, Manchukuo and Ryukyus, there are some things of some value here, along with common material as well. For instance, in the picture for the Ryukyus items where you also show the receipt, the C1 (that's the blue airmail underneath the green and the red ones), catalogs for $125 each, so that block of 4 catalogs for $500. (I'm looking at the 2017 Scott -- I don't know how the prices may have changed in the 2 later editions.)
In another picture earlier upstream, one where you show a red stamp at the top of the pic and a blue stamp at the bottom. It's the 10-sen stamp with the side paper still attached. It catalogs (in 2017) for $825 if it's hinged. It's been mounted on the page using something other than a hinge, so it's possible that it may have never been hinged. If so, it would catalog for considerably more. (Maybe 50% premium for that time.)
Catalog value is not what you would expect to sell for, either directly or to a dealer, but I cite those figures to tell you that there's some expensive material in there.
And there's a lot of other solid, low- to mid-range items you've shown as well. Very respectable, in my opinion.
The military postcards you've shown also have a bit of value. (These are actually "postal cards", rather than "post cards", because they were issued by the government and have the stamp image pre-printed into the design.)
I can't speak at all for the currency, although my sense is that it is not uncommon, but I don't know about any special items that may be there.
I would think that the paper ephemera (the military and school id's, etc.) would also have some value with paper ephemera collectors or possibly even the Japanese American National Museum (
http://www.janm.org/ ), especially because he was Japanese-American during this very ugly time in our history, and was here in Los Angeles, at the heart of the community hit so hard by the internment executive order 9066.