If someone bought at $20 I'd advise them to sell assuming they have capital gains to offset the loss. I might sell too although it is a small position as I just don't like acquisitive companies. This company has relied upon a high stock price to finance acquisitions and that is gone unless a miracle happens and they are cleared of everything and in my experience there will be payments and changes to governance practices.
A question that wasn't asked in the call is whether or not they have D&O insurance and what the coverage was. The class action is going to result in a settlement as those sorts of things always do once they clear the motion to dismiss phase. Probably do have insurance and the settlement will be covered but that has not yet been addressed to my knowledge.