Is it permissible for someone who went on a short sea trip and returned after the time for prayer had passed to combine and shorten the prayers upon returning home, or must he perform them without combining or shortening?

A man is not permitted to shorten the prayer upon returning to his home, because he is not a traveler, and shortening the prayer is specific to travel. As for combining prayers, if he has not prayed Asr or Maghrib until he returned, he should pray them before Isha, observing the proper order. In this case, Asr would be a make-up prayer (qada'), and he would be sinful for delaying it. However, if he covered a travel distance by sea for the outward journey and returned, he is allowed to delay Maghrib to combine it with Isha.