I totally understand the grieving process and the Rodas' family need to ascribe blame somewhere. Unfortunately, baring some sudden acknowledgement by Porsche they were negligent, that blame falls on Rodas himself.
Had this accident happened on a track, even during a high performance driving day (i.e. non-race event), then MAYBE I could support a law suit like this depending on the mechanical condition of a factory part. Tracks are built and maintained to drive vehicles like this at incredible levels. There are also safety personnel and protocols present to respond to an accident such as this (even though this appears to have been an instantaneous fatal crash). Surface streets are not. Pot holes, improper drainage, poor grade patterns, curbs, light poles, etc., are all present and not in the spectrum of responsibility for Porsche when selling a car like this. ALL of their documentation in all of their vehicles explicitly states to abide by all local and state driving laws and regulations.
Whether they were doing 95, 55, or 35mph, if the street they were on had a posted speed of 30 (for example), any speed above that is outside the scope to which the civil engineers designed that stretch of road to handle. People get lost in the concept that surface streets are not built to sustain driving in these types of manners. If a corner is posted at 20mph it is for a reason; design and surface material can only provide that level of controllable traction safely. Anything in excess can result in loss of control. Physics is physics.
All that said, it doesn't change how much this whole situation sucks. I am glad his brothers are helping finish out the "Fast 7" movie, even if it is a little weird maybe, but for their family I think that is a great thing. I certainly hope the Rodas family finds some support to help them gain some semblance of light in this dark time for them as well.