How does Owen use sonnet form to reflect on WW1 losses in Anthem for Doomed Youth?

Wilfred Owen uses the Italian sonnet form to reflect the losses of World War I by employing the first eight lines (or octave) to address the terrible cost of the loss of young men's lives in war and the last eight lines (or sestet) to address the effects of those losses on the men's homes and loved ones. Typically, with this form, the first eight lines introduce a problem or even a difficult question; then the last six lines resolve the problem or answer the question. One way in which Owen effectively uses this form to demonstrate the awful cost of war, especially this war in comparison with wars that came before, is that, while he introduces a problem in the octave, he does not solve the problem with the sestet. He cannot "solve" the problem of war because there is no solution. One of the messages of the poem, then, is that the loss of life in war can never be solved, can never be fixed. Once people have lost their lives, there is simply no way to redeem or mitigate that loss. Instead of attempting to solve the problem of war, the sestet only presents more problems and losses, compounding those presented by the octave.

How does Owen convey the futility of loss in "Anthem for Doomed Youth"?

"Anthem for Doomed Youth" is about the devastation of World War I. The poem is very much focused on the violence and extreme loss of life due to industrial warfare, with reference to shellings and rifle fire. Its focus on the futility of the experience goes all the way back to the poem's opening line, where Owen calls the doomed soldiers "these who die as cattle," a very bleak commentary on their utter helplessness in the face of mechanized warfare. That sense of helplessness is further invoked when Owen writes:

No mockeries now for them; no prayers nor bells; / nor any voice of mourning save the choirs, / the shrill, demented choirs of wailing shells

Here we get a sense of the ultimate desolation of those losses, so far from home, where even the soldiers' deaths are ultimately overwhelmed by those instruments of industrial warfare. Throughout the poem, Owen describes the horrors unleashed by World War I, and in describing this subject with such brutal and unrelenting intensity, he is able to convey its ultimate futility.