I don’t think he’s stolen your header, just used some of the same graphics (or maybe the same designer)
Look at your header where the crown is (the right of the name), and then look at this area on his header. Where you have the crown he has nothing obscuring the hand/cards.
This section of the header actualy looks like you’ve copied it from him and pasted a crown on top (I know you didn’t. but that’s how it looks)