How do I know the status of my friend’s warrant after he skipped?

A warrant remains active until it is executed. He should get an attorney. That was 35 years ago, and there have undoubtedly been many changes since then. The evidence and witnesses against him may not be available anymore. But no one is going to know, basically, unless an attorney is hired. You can go view the court file at the county courthouse, most likely, and see the police report and other documents, but you might have to have them scan it so that you can look at them. Back then we used microfilm, and you might have to look at it in that form.