With codeplex gone it can be a bit hard to find the real download for some things. I had to search an old server archive to find this.
Php manager 1.2 x64,
PHPManagerForIIS-1.2.0-x64.msi
This is the original v1.2 64bit download from 2012.
Enjoy.
I also found the older 1.1.1 download should you want that instead,
PHPManagerForIIS-1.1.1-x64.msi