Proper successor of Pokorny and Brugmann/Delbrück
I found proper successor of Pokorny's Indogermanisches Etymologisches
Wörterbuch and Brugmann's/Delbrück's Grundriss der vergleichenden
Grammatik der indogermanischen Sprachen called Indogermanisches
Wörterbuch by Gerhard Köbler. Its Vorwort contains complete PIE
grammar. This book is available here:
http://www.koeblergerhard.de/idgwbhin.html It supersedes too Dnghu's
Europaio/Sindhueuroipaiom.