Kabuliwala and Mini's friendship was distant from this world. He was like a friend to Mini. A little girl of 7-8 years and Kabuli Wala came to his home, gave him nuts, and talked with each other for hours cracking an equivalent joke all day then also laughing hard at that joke and playing games all day.
I don't think that anyone who may be a big man, even a father, would tease an equivalent joke as his daughter's but yes Kabuli Wala did.
When mini grew up and when she was getting married, Kabuli Wala felt sad for himself because he was a father of a woman also of mini's age and therefore the conclusion we get that Kabuliwala just treated mini as his best daughter. Because they shared the bond with each other like father and Daughter.