Being not weak in faith he considered not (μὴ ἀσθενήσας τῇ πίστει οὐ κατενόησεν)
The best texts omit οὐ not before considered. According to this the rendering is as Rev., he considered, etc. Being not weak or weakened: (Rev.) is an accompanying circumstance to he considered. He considered all these unfavorable circumstances without a weakening of faith. The preposition κατά in κατενόησεν considered, is intensive - attentively. He fixed his eye upon the obstacles.
Dead (νενεκρωμένον)
The participle is passive, slain. Used here hyperbolically. Hence, Rev., as good as dead.