This is a loaded question so its hard to answer. The answer is yes and no and who cares. Lindsey has changed like all of us change over the years. I remember an interview he did during Mirage where he stated he saw his future of never touring after the age of 40 LOL
I think even he admits her solo success bothered him. I think the jealousy definitely made him regret helping her. He has said this numerous times in interviews that it was hard for him to help her but he still did.
After Tusk I dont think he helped her to the degree he did in the earlier years. And to be honest, it would have been really hard to do it anyway. She was not sober in the early Tango days.
If he could turn back time would he have still done it? Probably so because in those early days her success was his success. Did he regret it later on? Yes. Does he care today? Probably not. Lindsey seems at peace these days and not into fighting but more setting the record straight. He would go back to the Mac and help Stevie if asked to do it. Although it wont happen.
Strange enough Lindsey even helped Stevie when she was not around making his voice sound like hers and doing clever things in layering her voice in areas on Tango. So even post Tusk, he was still a team member making the group effort the most important thing. Stevie's songs on Tango suck not because he did not want to help her but that she contributed bad songs and she was not around in the process to make them better. You can put lipstick on a pig but its still a pig
I also think he worked his ass off on SYW and she has some great songs on there (sorry Homer). BTW, stop hating on Lindsey for the way he sings and plays guitar (come).