In South Asian cricket, we have seen many players' careers destroyed due to politics. And here every board has bad politics. I can't find any reason not to keep Sadab Khan in the squad. As the series will be held in Pakistan. And Pakshithan's pitch is helpful for spinners. Pakistan management should have given Sadab Khan a chance in this series. On the other hand, I am not surprised to not keep Fawad Alam on the team. We know that Fawad Alam is a good player in the Test format. But don't forget he is 37 years old. Perhaps now the Pakistan management does not want to keep any older players in the squad. But if Fawad Alam gets a chance in this series, he might have been able to perform well. England is a strong team, against such a team, experienced players are definitely needed.
All the South Asian teams have problems with selection. Pakistan needs a new and a good captain for their team. They only makes it to the finals owing to good fortune and their bowling lineup and they need batsmen. India has fired its selection committee due to the team's terrible performance at the T20 World Cup. And I'm certain that Bangladesh, and Sri Lanka are in a similar scenario. I'm not sure why the selectors are disregarding Fawad Alam, either. He had one opportunity to be a member of the test squad, but he only scored 25 runs in two innings. His subsequent play in the domestic contests was likewise subpar. This may be one of the causes.
If you think about Pakistani squad who can you think of being a captain of Pakistan cricket team apart from Babar Azam. Right now he's good to lead Pakistan and he has proved his strength through his game many times . He might be not in form from couple of matches but still the way he leads and stands by his team is worth appreciating.