The "Former Teacher" is a real teacher, but of one of Mathematics and with no TEFL cert of training in hand. His accent is strongly Scottish and even for me hard to understand. So, I would not rely too much on any "expertise" regarding ESL from such a person. Above all, merely being a native speaker with no further qualifications for teaching ESL does not make one a real ESl teacher.

San Migs is another case in point. "Former Teacher" as a former teacher with too much time on his hand for heavy drinking now as he is retired now is rude due to hs heavy drinking. He has been rude to me several times as well while talking repeatedly to him on Skype several years ago.
He doesn't seem to know that he is; people with a habit of heavy drinking problem often do not realise that they are.

It's exactly for this very reason that I refrained from having any further personal contacts with "Former Teacher" already several years ago..

I feel no need whatsoever to respond in depth to your derogatory opinion of me. You can be sure I have a similar opinion of you. What's more, I'm not at all surprised you have responded in this way as I know you are not a good person. I'm glad that you have been reduced to the ignominy of having to blow your top in public. I'm glad that I have caused you to do so. You are not only haughty and elitist, but also one who enjoys blowing his trumpet.