To simplify the task, we can structure it as follows:
1. Prompt the user for input.
2. Check if the input contains only alphabetic characters (and spaces if necessary).
3. If it does, reverse each word and return the modified string.
4. If it doesn't, prompt the user to enter a valid sentence.
Here's a simplified version of the logic:
```python
def reverse_words(input_string):
# Check for non-alphabetic characters
if not


