It makes no sense at first (or second glance). It is not "English" in any correct form. Cummings is known for playing with words and grammar so that their meaning is almost impossible to decipher unless you know him (the poet) plus the background of the poem. Understanding poetry like this requires poetry analysis, more than a knowledge of English.
This poem is about his father. And one interpretation of the sentence containing 'they's of we' is Cummings is describing how the father is pushing away friends and family who were close to him. ie. The father was turning the "we's" (Cummings is playing with "we" and referring to people close to the father) into "they's" - people more distant (Cummings plays with the word 'theys' to create the idea of 'them'. ..... 'We' being people close, theys/them being people distant.)