As to what your friend might mean by "after theory": I understand it to be a strain of thinking that speculates on the end of theory (especially postmodern and poststructuralist theory, which flourished in the 1980s and 1990s) and examining its impact on the fields of literature, philosophy, etc. If your friend has a similar idea in mind, Terry Eagleton's After Theory (2003) may be useful, but I don't think it has much, if anything, to say about poetry. Of course, positing the idea that theory is "over" and even assuming that theory "has" an "end" is highly contentious.
As for texts related to deconstruction and poetry, some helpful texts may be Sovereignties in Question: The Poetics of Paul Celan (2005) by Jacques Derrida. Altered Reading: Levinas and Literature (1999) by Jill Robbins explores how literature (with a section on poetry) relates to the ethics of Levinas, though little is said about deconstruction. Wounded Fiction: Modern Poetry and Deconstruction by Joseph Adamson might also be helpful, though, being published in 1988, it isn't very contemporary.
I'm unsure what you've already read, but it could also be helpful to read what what Derrida and Heidegger have written on language and poetry. This would include Derrida's Writing and Difference (1967) (which contains the chapter "Edmond Jabès and the Question of the Book" and discusses poetry) and Of Grammatology (1967) (in which Derrida introduces deconstruction) and Heidegger's Poetry, Language, Thought (1971).
If you have access to JSTOR, one helpful article may be "Open(ing) Texts: Deconstruction and Responding to Poetry."