Contact your state bar association to see if he is perhaps still practicing in another city or county, or post his name here and city state, and I can check some databases to see if he is still around.
Is this attorney the official executor of the estate or merely someone who just helped draft the will and is not executor? IF he is not executor, then you can still submit the will for probate if it is signed and has witnesses's signatures.
What makes you think the will is not valid?