Does what happened to him—waking up after the time for Fajr prayer had passed, despite his resolve to rise for the prayer and his struggle against sleep—bear the same ruling as someone who intentionally delays the prayer? And does his delay of Maghrib prayer due to an impediment on his hand and the passage of time while waiting for the impurity to be removed, with the prayer's time nearing its end, also count as an intentional delay of the prayer?

The sleeper who misses a prayer is not considered to have intentionally delayed it. However, there is a difference of opinion regarding sleeping after the prayer's time has expired but before it is made up. Waiting for urination to stop to perform the prayer is valid, and a lack of time does not negate the condition of purification (taharah), nor is purification valid as long as urine is still flowing. There is nothing in what you mentioned in the two questions that constitutes disbelief (kufr).