The relevant section in the FAQs is the following.
Can I use web fonts for my client websites?
The Terms of Use do not permit reselling beyond December 31, 2019. After that time, the client's website must load Adobe Fonts from their own Creative Cloud subscription to ensure that there isn't any interruption to the font licensing or web font hosting.
In the terms of services it is the following.
3.3 Use of the Licensed Content by Publishers on Whose Behalf You Create Websites.
Publishers on whose behalf you
create Websites must purchase their own subscription to the Service to continue using and displaying the Licensed Content
on their own behalf upon completion of the Website(s) . You may not host the Web Fonts or Web Projects for the Publisher
or resell the Service to them.
3.4 Obligations, Limitations, Restrictions, and Prohibited Uses of the Licensed Content.
[...]
(E) Prohibited Uses of the Licensed Content. Except as may be permitted pursuant to any open source license terms applicable to certain open source components that may be included in or distributed with the Licensed Content, you are expressly prohibited from:
(1) hosting the Licensed Content on your own server or other self-hosting option or service;
[...]
(11) hosting Web Fonts or Web Projects for your own customers or clients, or reselling the Service to them; and
The result is the same, the client requires a Creative Cloud subscription. Not sure why they would think what they are doing is allowed, this is neither hard to find nor hard to understand.