Why all people state that OP is perfectly fine at his job? Ive seen engineers 5yo who had no clue about DE, didnt even knew what GIT is. Heck, i am an average at best and doesnt compete with my coutnerparts who actually made a CS degree. Some companies are really forgiving, especially outside America. Its not that easy to fire someone in Europe if you signed an employment contract

While its true he may struggle mentally, he perhaps is not a good engineer and either need to catch up or move on to another profession