there are a few ways, you can either trace the session then tkprof which is 100% accurate or you can check v$sesstat of the session executing the process and check for statistics about commit and fetched rows

but just ask the guy who wrote the code, does he commit for each row modified? he would answer as a fool yes or no because it's not a tricky or offensive question and you are not telling him he is doing something wrong (yet), once he says yes then you can start bash him