"Rules: You must use a while loop to solve this kata."

Why, a for loop or recursion could solve this as well? Also how do you expect to enforce this?

You're not using the Codewars Python Test Framework, making this kata impossible to complete.
https://docs.codewars.com/languages/python/codewars-test/

• Missing solution and test framework import

• Missing useful assertion messages

• Duplicate 1

  Duplicate 2

Description should be language agnostic. There is no reason to have the function name ( which may vary between languages ) in there.

Please use zero-based indexing - like all of Python. You can simply specify even indices are added and odd ones are subtracted instead of the wrong way 'round.

1. There are no mentions of which are the letters that are vowels and which are consonants.
2. There is also no mention about case sensitivity. There are cases like that in sample tests, but you shouldn't rely on tests to explain specs.
3. This is basically just Vowel Count + Count consonants.