Read the title again. How many times would you expect to read an article asking if a man could befriend a younger girl? Not many times, this is because of how normal it is for a guy to have younger female friends but if a woman has a younger male friend, she's labeled a cougar.
The tv drama Dobara explores exactly this topic. Hadiqa Kiyani (Mehrunissa) or Mehru as she prefers to be called, befriends Mahir (played by Bilal Abbas), who is much younger than her. Everyone, both inside and outside the family automatically assumes they are in a relationship, even when Mehru makes it clear that they are not. What is interesting is how her son is angered by her mother's close friendship with Mahir and takes matters into his own hands, while the daughter is supportive of their friendship.