The only way to really start to shift the culture (seeing as how you are an outsider in terms of the family relationship) is to start circulating books, CDs or DVDs to the "powers that be" that focus on creating a better, more streamlined business. Seminars and workshops are also good.
In the meantime, you can listen, read and learn as well, and use your new-found knowledge to find a better business to work for.
Generally, you'll need to hope for the best but be prepared for the worst. There's the old adage about "killing the messenger." At the end of the day, it is their family business--and resistance to change will be high.