That is almost impossible. Here are the conditions for Pakistan to qualify - :
1) Bangladesh will play 3 match series with South Africa after 3 with India. If Bangladesh manages to win 2 out of these 6 matches, then no chance for Pakistan.
2) If Bangladesh wins only one of those, then Pakistan will have to whitewash Sri Lanka.
3) If Bangladesh doesn't wins any match. Then Pakistan will have to win either by 4-1 or 3-2.