spoken and written english are very different things, i may not speak good vocab in english but as i write, i start to get all those exact words in my head
secondly he may have written in urdu and may have got it translated
or he may have written in english and may have got checked by his helpers even mushy when writing his autobiography had the help of professional people
thirdly he is not your typical paindu who is not educated, he was educated as pharmacist in Karachi university, now he is not your typical paindu plitician which you are so used to