Holmes could be able to come to conclusions who is this visitor, and what brings him here like he knew him the whole his life. (?)

у бедного К.Дойла - deductions

what brought him here
his whole life

Ну а насчет "всю жизнь" это учитель явно перестарался. В русском переводе нет ничего подобного.

Выводы были всего лишь "масон, адвокат, холосты и ...астма"

Interesting. I didn't open the original.

all his life

Holmes managed to draw conclusions about who the visitor is and what brought him here as if he had known him all his life