Ordinarily, I would say that this sinks his chances, but he won in 2016 in spite of things like his "grab them by the pussy" remark. I felt like the other comments he made during that conversation (where he explained that he was trying to seduce a married woman for no other reason than "want[ing] to fuck her") should have done much more damage with the Protestant voters that he was relying on, but it didn't seem to have any effect.
On the other hand, his 2016 antics may have been seen as a more earnest approach than the usual slick and dishonest blather that we are used to from politicians. Which would mean that the act will not have the same impact now, and things like the lawsuit --and his refusal to let the 2020 election go-- may make prospective voters feel as if he is too distracted now. He's also quite old, but that won't hurt him if he's running against Biden.