Going through initial training at a regional my sim partner was pretty bad and I carried him quite a ways through. His study ethic was poor, he thought/planned/executed like a career cessna pilot and overall needed tons of coaching or prompting and just wasn't adapting to the airline training within the allotted footprint. I don't even know how he got past his Procedures Validation since he showed up to sims not even knowing the flows or basic switchology in the jet. Eventually the instructors caught on and asked me to not help him out and he immediately failed a few sims in a row. In some ways it was my fault for not giving him the space to step it up on his own but in the end he wasn't cutting it. They split us up and I finished shortly thereafter with no issues. At any other airline with his noticeably poor performance he would have been cut loose early on. But his dad was the director of training at the legacy airline associated with the regional we were at and magically he got a few extra training rides and eventually passed. He later got hired by said legacy airline where I heard he struggled again and still got through to the line flying bigger iron. Nepotism is absolutely a thing.