My parents died within months of each other. Their lawyer no longer practices. How do we locate their will?

Some lawyers keep a signed, witnessed and notarized copy of the Will or, more rarely, the original.  You can ask who took over the practice.  I few courts will keep a Will on file for a fee.  Most people keep their Wills at home, perhaps in a safe.  Some people keep them in a safety deposit box.  Hunt.  If you do not find it, ask a local probate attorney to help you file an application to determine heirs and probate (prove) the estate.