Essentially, I want to know if the copywriter can or should help us craft our 'why'.
The "how and why" is not something even the best copywriter can help you clarify. If you feel that the crux of your value proposition and reason for being is not connecting, that's likely because you are still either unsure of who your customer is, not sure of which features or benefits to emphasize, or other more core issues to your business.
I have a history of helping translate very complex ideas into simple to understand terms. Starting with how this thing called the "internet" (in 1995) was going to change the music business to how "social media" (in 2004) was going to change how fundraising works via many people giving small amounts of money.
I'd be happy to do a call with you to hear your "why" and see if I could help you get some added clarity.