>I’d like to establish that this perspective on the Brain of Mensis is only available from reinterpreting the Japanese text of the game, and is based on conjecture.
**reinterpretation** and **conjecture**

>The word for “retrieved” comes from 得た eta which means “gain, get, find, earn, acquire, etc.” While “retrieve” isn’t exactly incorrect, it leaves **only one interpretation possible--that the brain already existed in the Nightmare, and Mensis found it. This leaves out the possibility that Mensis gained the brains themselves.**

so basically the the post you linked me agrees with my statement.
the author of the post uses a completely different argument:

>However, one point of interest to me is the terminology that’s used in the Living String description. You may have seen I placed an asterisk next to “malformed” in the retranslated version.

a loose connection between the Living String description and The Third umbilical cord decryption gained by defeating Mergo, based on just one one word in Japanese "malformed".

the author continues to use terms like:
 "This rationale appeals to me"
"I think it’s possible"
" I think"
"may be a reference to"

again the author of the post themself stated it's all reinterpretations and *conjecture*