The best thing they could do would be to quietly semi retire. Never make any large public appearance again. Quietly release music. If they go public again, she will go public 10x as hard and anyone Axl has pissed off in the last 30 years will also go public 10x as hard. This would destroy the reps of Slash, Duff etc by proxy.
This lawsuit isn’t about money, given her statements, it is about ending Axl as a public person. This isn’t a battle Axl can win in the court of public opinion. In the court of law, perhaps. But a lot of people still hate Axl and will readily believe the worst because of the bad reputation he cultivated in the early 1990s.