What are you not understanding?
Your parent CANNOT enter the U.S using a visitor visa with the INTENT to STAY and adjust status!!! It is visa FRAUD and will result in a lifetime ban for your parent.
It's a big fat no. Your ONLY option is consular processing. Period. End of story.
What isa CS1 visa? Are you talking about CR1?
This is a DIY site, the majority of us have done the entire process on our own. As long as your case isn't complicated, then no reason for an attorney.