As Nietzsche said; alcohol is the opium of the masses. However he may have also agreed that punting is the opium of the male masses. He did think that sex was a great thing to partake in and perhaps contracted syphilis from it which killed him at 42. His point was alcohol makes it harder for people confront and address what makes them unhappy. Similarly, punting can be a form of delightful and expensive escapism from things that you want to avoid or make you unhappy.
Maybe your friend should spend the money and time he spends punting on looking for a better fitting or exciting job, or tackling the work issues that bother him.
Nietzsche would have frowned on regular punting as he probably thought it was better spending the money and time on addressing issues or seeking out a hot relationship, or on spicing up an existing relationship. The delights of a punting quickie are so short. In a proper relationship, even if not a long term one, there are other dimensions of sexual fulfilment that can be explored.
Dopamine levels can be low for a range of reasons including depression. Punting can induce a dopamine spike to counteract this but it is not a long term solution.