Cowlicks in hair

Can anybody suggest me any type of gel or spray that can help keep cowlicks down, My son has one that crept up about a year ago and will NOT go away no matter what I do to his hair, it’s horrible.😣 I know nothing about little boy hair so I wasn’t sure what I could get that maybe would help keep it down.😂

Also he has a thick head of hair if that makes a difference in anything, my mom has this spray she’s tried to use and it works for about 20 minutes before his hair sticks straight back up.