I don't know if this will work, but you can give it a go and see if it kick-starts the indexing process. This will only help if resetting your spotlight config to use your client's custom mount point is for some reason necessary:
From:
https://support.apple.com/en-au/HT201716
If searching your Mac doesn’t return expected results, rebuilding the Spotlight index might help.
Choose Apple menu () > System Preferences, then click Spotlight.
Click the Privacy tab.
Drag the folder or disk that you want to index again to the list of locations that Spotlight is prevented from searching. Or click the Add (+) button and select the folder or disk to add.
To add an item to the Privacy tab, you must have ownership permissions for that item. To learn about permissions, choose Help from the Finder menu bar, then search for “permissions.”
From the same list of locations, select the folder or disk that you just added. Then click the Remove (–) button to remove it from the list.
Quit System Preferences. Spotlight will re-index the contents of the folder or disk.
LGA1150 Xeon E3-1220Lv3 || 32GB Unbuffered DDR3L-1600 || System on USB3 || Intel C224 via software RAID and 4 disk backplane
HP ML10v2 Xeon E3-1220Lv3 || 32GB Unbuffered DDR3L-1600 || System on SAnDisk Extreme || HP controller w software RAID and 3+1 disk backplane