Is the aforementioned hadith from the Prophet, may God’s prayers and peace be upon him, regarding praying twelve rak'ahs and a specific supplication thereafter authentic, and what is the authenticity of the prohibition against teaching it to the foolish?

The Hadith is weak in its chain of narration (isnad) and text (matn). Amir ibn Khidash al-Naysaburi was the only one to narrate it, and he was known for his objectionable narrations (manakir). He narrated it from Umar ibn Harun al-Balkhi, who was abandoned (matruk) and accused (mutahham). Furthermore, it contradicts authentic Ahadith that prohibit reciting the Quran during prostration, therefore it is not permissible to act upon it.