My son as well - he was the only boy in a troop of girls, nieces, cousins, etc. - all of them had dolls and girl things to play with - we ended up buying him a boy doll to play with which he loved. He played dress up with them, wigs, heels, dresses, etc., because that’s what they did.
He is now an IT specialist, hard core weightlifter, gun enthusiast, loves kayaking, motorcycle riding and every other “male-based” activity. He also loves girls but is having a hard time choosing which one to settle down with (mid-20s so he has time).
We did the same thing. Their girl classmates in pre-K had Barbies to dress up and they wanted the same. So we got them Barbies with lots of clothes. The girls would come over and they'd have dress up Barbie time.
A few months later I found my sons standing over the garbage can cutting off their Barbies' hair. They then bent them into a right angle, pointed them at each other, and the Barbies became guns. That was the end of their doll phase. It was all so freakin' cute and simply children being children.