It must be a good bunch of stuff, since "she" ordered me to capture it for her.
A sidebar at the left at the link offers the ten volumes and a master index (the last & smallest file) as .pdf files, so you can right click and "save target as" to get them on your local machine. Total for the full set is about 173 MB, so people with a slower connection might want to download one or two volumes and see what they're getting before doing the full set.
Each separate volume has its own index at the front. The sheet music is mostly legible enough, although one might get dizzy from reading from the slanty pages, some of which tilt left at the top and right at the bottom, and some other way in the middle. I can understand the difficulty of getting straight scans on that many pages, as I've been doing a bit of "archiving" myself recently (although mostly not music).
The songs I've looked at should mostly be familiar to those in the US who listened to much radio up through sometime in the 60s, and include movie and show tunes along with some "popular" stuff. So far as I've been able to see, there is no separation of different kinds of songs in the various volumes.
There is an index by composers begining at page 101 of the master index, following a few comments, although lots of the sheet music pages do not show any attribution.
At page 104 of the master index, it is claimed
"There are 4,596 tunes which are not in Gb (and, one which is!)"
(Most are in C, indicting perhaps that they're from piano sheet music?)
The index does not convert readily to text or doc format, but that's a common problem with "column layout" stuff, and the text layer seems to be relatively complete so short bits of text can be copied out fairly readily. Sheet music pages extract okay (as .bmp for a few I tried) to my ancient Photoshop Elements, and should print okay direct from the pdf.