Is it possible? Sure, but, traditionally, his assassination was more an inside job and if Claudius even knew about it would have likely indicated his involvement, at the very least his approval, and Claudius wider reputation wasn't really of one that people were going to ally with.

If he knew, why did he do nothing? Well Claudius (pre-emperor) was a laughing stock for most of his life, though he'd gained some respect among intellectuals due to his writings, but outside of that, he wasn't well respected. What would he have done with this information? Gone to Gaius? Gaius would have possibly had him killed. If he goes to anyone else then he's part of the conspiracy at that point and if your conspiracy does not succeed, you very often end up dead. It would be a considerable 180 from our modern understanding of Claudius if he knew of (and did nothing) or was part of the conspiracy.