life after death

ive been teaching some kids in a grade thats below mine and weve been discussing religion. unfortunately because i had food poisoning (and also my friend was extremely talkative and i couldnt say a word) i wasnt able to hold a proper conversation with these kids. they all had really interesting opinions on some questions that i managed to ask. some guy who was sitting right in front of me really fasinated me with his answer to a question that i asked. i asked what he thinks happens after we die. he replied that nothing. that we just become nothing. this answer was kind of depressing and i was a bit shocked because he seemed like a cheerful person. but he elaborated by saying that it doesnt make him think that what we do hold no meaning. maybe some people think that because nothing happens after we die everything that we did when we were alive is meaningless but he had a different opinion, he didnt even seem sad. he was totally fine with becoming nothing as long as his life was fulfilling. maybe he is right. why would our legacy matter if were not here to withess its impact?