watching someone else overtip

[the machine]

last session a guy sat down at my table and i think it may have been about his 2nd time ever playing.

after dragging a smallish pot (50-70) he tips the dealer 15$ as the dealer leaves. i get sad because i see my EV going down the drain if the guy keeps tipping like this.

i dont say a word to him as its his money and he can do as he likes with it. but at the same time im thinking about how this might be a bad thing for the table if he goes on a heater and takes alot of the money out of play with some big tips

is there an amount where you would chime in and say something. either directly; you dont need to tip so much, or indirectly like big tipper over here?