Conversation so far:
When did he reunite with Lilith and Frederick?
In "The Show Where Lilith Comes Back" (1994), Lilith surprises Frasier by dialing to the radio show.
What does she say on the radio show?
They later make love in a hotel room, but end up regretting it, prompting them to part ways again.
Is he reunited with Frederick?
They decide to remain friends and help each other raise their son Frederick (Trevor Einhorn), who also appears occasionally in this spin-off.
Does Frasier have a good relationship with Frederick?
Frasier is proven as unathletic and bad at softball, which he reluctantly admits to Frederick.
What else happens in the reunion episode?
In "Adventures in Paradise, Part Two" (1994), Lilith gets engaged to her fiance Brian (James Morrison), much to Frasier's dismay.

Question: How does Frasier react to the engagement?
Self-contained rewrite: How does Frasier react to Lilith's engagement in the Frasier episode "Adventures in Paradise, Part Two"?