What Attracts Ticks?

I would say it's the sweat glands and moisture on his clothes. Bugs in general like cool damp places and his sweat glands make his shirt/clothing probably nice and damp and cool. So they may cling to him to keep cool. I would check a local vetenarian. Woman tend to sweat less therefore not producing as much cool damp areas on the clothing.

They also sense motion since they can see some inches away, so when they see you they jump toward you hoping to latch on, even jumping up to 24 inches.

Hi, Does he wear a cologne or body spray? God Bless