Since I knew that Google had some issue with pages with pages that load contents via AJAX I tested my client website with Google Search Console and How Google use my pages. From that tool Google seems to see just the body, since all the contents are loaded via Ajax.
I did a little research and found this page from Google https://developers.google.com/webmasters/ajax-crawling/docs/learn-more
but at the top is reported that this guidelines are deprecated and links to a new page https://webmasters.googleblog.com/2015/10/deprecating-our-ajax-crawling-scheme.html
This article basically says that if a modern web browser can see the page Google also can see the page.
At this point it could be that search console tool is outdated, but I'm not 100% sure that Google can really see AJAXed content.
Any way to test it?