I do not know who Tommy is. I wish I could share the sentiment of how dreadful it is to miss Tommy but I am afraid I cannot relate.

[Well, he can relate to the 'missing someone' part, since he misses Leah terribly and he misses her harsh words and those moments where a friendship was simple like that. Where his older self was a magpie instead of an altered version from another universe.

But Leah is not gone like Billy's friend Tommy is.

For a moment there's a sound of something knispering, followed by the obvious sound of Loki eating potatochips and making it his job to be extra loud about it.]

What kind of things? The word 'things' can refer to a lot of different things, you see?