Palace's argument is centred around a number of things ;
Palace do not share any employees, players, etc etc - in other words on a day to day basis they are not collaborating with any of Textors other clubs. Now we have had dealings with them - eg Plange's loan to Molenbeek, Jake O'Brien same and then permanent transfer to Lyon. I imagine that UEFA are examining those deals as part of their investigation. So ultimately not part of a multi club set up.
Textor does not have control of the day to day running of the club. Yes, he is the majority shareholder but only has the same voting rights as Harris, Blitzer and Parish - with Parish having the final say in the decision making process. Again, I would expect UEFA to be examining Palace's constitutional documents that will demonstrate that this is indeed the case.
It's in Textors hands to the extent that if UEFA arrive at a compromise solution that involves him, then yes, it's down to him. So far it's been reported that he's offered to put his shares into a Blind Trust - rejected by UEFA as it's past their ( ludicrous ) deadline, to sell his shares / dilute his holdings or step down as a Director.
Although he can be seen to be the root of the problem, he does appear to want to do what he can to ensure Palace can take their rightful place.
All guesswork on my part, but I'm hoping UEFA are giving Palace every chance to find a positive outcome.
Fingers crossed !