I'm very sorry to hear about your Aunt 51years. That's a terrible story.
The problem with any defence for Helen is that, even with the recent law change, there are no real 'facts' to present to a jury anyway. No-one has ever witnessed anything that could be described as abuse. Helen's always publicly agreed with his decision making (not driving/not working/not taking Henry to school) so it would surely be impossible to prove that any of it was coercive behaviour on Rob's part.
Rob's managed to convince everyone that Helen is the most important person in his life. That everything he does, he does for her. He's taken on her child, he's sacrificed his own job to help out in her family business, he's put aside his own feelings about his mother to accept help from her when Helen couldn't cope.
The Ambridge residents, even those who can't quite put their finger on why they don't like him, have given him credit for his heroics during the flood, consider him a team-player where the cricket's concerned and grudgingly admire him for taking on Helen and Henry.