I wonder if the 'Whoever' informs your question about who is doing the following and being. Rather than specifying a single person and asking who that one person is, the statement then would address a general reader. No matter who it is 'up there' looking down reading his words they ought to keep a strong heart and carry on.

To me the lines read almost like a template: "But a day or two more, for [I] see the frame all wasted and sinking, and the yellow-blue countenance [I] see". By leaving out the pronoun "I" the reader is included, and 'see' becomes an imperative, instructing the reader to 'see' for themself what the words describe. The image is drawn into further light this way, because it matters not who is doing the seeing, only that the wounds are being seen.