I would [ I hope] get down on my knees and
- beg him to finish the Silmarillion
- make it as large as he has imagined it to be
- keep the pre-numenoreanless world flat!!!!!!!!!!!!!!!!!
- forget writing letters to all of those folks until the Silmarillion is finished.
- Don't worry about an elvish glossary/dictionary till the Silmarillion was finished!
- please finish the Silmarillion
Of course I would prob go brain dead like everyoneelse, but assuming I didn't. Those are the words I would use to make a fool of meself.