i can't stand anymore

If I were on such situation, I would tell my superior about my co-worker’s behaviour it’s because it is not fair to work harder and harder and in the end, no one is helping you because the other worker is plain simple lazy. I would also confront that person, whether or not he/she will get offended on what is real, still it’s the best way to correct his/her wrong doings. It’s definitely unfair because he/she got hired to work on the firm and yet, he/she is not working the job right.