I've never personally used Sheiko, but a number of the lifters at the gym I go to do. It's entirely possible to do Sheiko without "Help".
Sheiko is very carefully planned out to allow you to work with high volumes without overtraining. This is done by rotating hard, meduim and easy days (measured by the average intensity x total reps), alternating weeks that focus more on volume, and weeks that focus more on intensity (although the intensity weeks still are more volume oriented than most other routines), and keeping the average intensity of any lift done at ~70%, which Sheiko believes helps prevent overtraining (So even if you have sets at 80-85%, the average of all sets done is typically ~70%).
One thing to keep in mind about Sheiko is that the routines given are example routines, of what a routine might look like if it was put together using Sheiko'a principles. As such not only can you modify them, but it's expected.
The means:
1) if necessary you can adjust the weight up, or down, I.e. if it calls for doubles at 85% and the weight feels like a joke, or rediculously hard, you can change it...but you better be able to complete the presribed reps and sets.
2) if necessary you can drop the second round of an exercise. So if the day is Squat, Bench, Squat, but you're feeling dead at the end of benching, you can skip the second round of squats. Alternatively, if it's possible/convenient, you can do these at different times of the day, I.e. Squat, Bench in the morning, and the second squat workout in the evening (but don't change the order).
3) You can change the assistance work to suit your needs. For example, it's pretty common to switch the suggested assistance with back work like pull-ups and face-pulls.
4) You can vary the main exercises. For example, instead of benching all the time, you can do some narrow grip work instead. Also, I've heard that pulls to the knees is more effective for lifters who pull sumo, and that it's acceptable to switch pulls to the knees for deficit deadlifts/