You can not speak to him at all?
You could keep going without speaking to him or Jake there.

Please email supportdos@larian.com, with a brief description of the problem and the report.zip file generated by the D:OS Analysis Tool (for the PC version). The report will contain system and game information, as well as your saved games. To reduce the file size, you can delete most of the saves from the zip; leave a save before using the Enlightened Amulet to get past the barrier (or your your latest save if you don't have a recent save then), and maybe one just before Thelyron left the clinic.

For Mac, to get system specs you can use the 'System Report' button from the 'About This Mac' Apple menu item or the 'System Information' app (in the utilities folder).
Saves can be zipped by right clicking the folder(s) and selecting Compress, in the folder:
~/Documents/Larian Studios/Divinity Original Sin/PlayerProfiles/<ProfileName>/Savegames