2003 Chevy Trailblazer Front Axle

Drive Train Axles Bearings problem
2003 Chevy Trailblazer 6 cyl Four Wheel Drive Automatic

My mother has a 2003 trailblazer and has to replace the front axle again. It's been replaced twice in the past year. She went outside last night to find grease all over the front tires. My dad looked at the underneath of the car and said she needs another axle, that it's broke. What could be causing the axles to keep breaking? Also, the car feels like it's all over the road, especially when on the highway.

Thanks for any info.