A reply on ancestry's Facebook page from about a week ago:
The price you pay when you purchase a DNA test with Ancestry gives you access to your full ethnicity estimate as well as your DNA matches. There is no added cost to view your matches. However some extra features are available to subscribers. The article below advises further on this.
https://support.ancestry.co.uk/s/art...-Subscriptions
So if he doesn't have a sub, he can view the list of his DNA matches, and contact them, and see the lists of shared matches, but doesn't get full access to the matching people's public family trees.
Also, he can download his raw DNA data from ancestry and upload it for free to sites such as My Heritage (until 1st Dec this year) and FamilyTree DNA, which will give him more lists of matches. You do get some info about matching people's trees on those sites without a sub. Info on how to download the raw data:
https://support.ancestry.co.uk/s/art...g-Raw-DNA-Data
And I've just found this maybe most important piece of info - he can invite you to be the "manager" of his DNA results and then your sub can be used to view matching people's trees etc. I have seen managers in my list of matches but I thought you could only be a manager if you ordered the test in the first place. Very interested to see how it actually works!
https://support.ancestry.co.uk/s/art...ng-DNA-Results