If moms auto-like every post, then how is that a relevant signal? Everyone has a mom. That would mean every post is getting penalized in the same way (which effectively means no posts are getting penalized).
And if circumventing this was as simple as excluding his mom, wouldn't the effect be even greater if he excluded all non-technical friends and family?
Which pretty much just means you're posting this for the greater public, which presumably a lot of users of Facebook's API already do. Since his intention is for his content to be seen by the greater public, then... go ahead and tell the API that?
It's a great angle for an article, and it's very shareable, but he provides no data (even though he seems like someone who would have all of the data).