For scribble drawing I use Artline pigment ink pens with 3 different size 0.1; 0.3 and 0.7 to make scribble lines more plentiful.
To be able to draw a portrait like that using just those pens is true artistic talent. There is no photo for us to see how accurate the portrait is but you have managed to make it very lifelike and fill it with emotion so i'm guessing that it's very close.
Thank you very much @niallon11 for your great encouragement! The relevant photo was showed sometimes in clips but quite fast, I hope you can see it.