Alsonso is surprised that everyone is falling asleep, and he wants to sleep too so he can forget his son is dead.
Alonso is the King of Naples. He and Antonio, Prospero’s brother, betrayed Prospero by taking his kingdom from him. When they show up on Prospero’s island, shipwrecked, they have no idea he is there. They are saddened by the loss of Ferdinand, the king’s son, and disoriented both by the enchantments of the island and the ordeal.
Alonso is very upset about Ferdinand’s death. Nothing anyone says can comfort him.
You cram these words into mine ears against(110)
The stomach of my sense. Would I have never
Married my daughter there! For, coming thence,
My son is lost … (Act 2, Scene 1)
By this he means that he wishes they had not made the trip to see his daughter get married, because in marrying off his daughter he lost his son. Now he will not likely see either again.
While Alsonso is being grumpy and imperial, the others are either trying to figure out where they are or what is going on, except for Gonzalo and Sebastian, who are chatting nonsense about colonizing the island. Arial, Propsero’s magical servant, begins messing with the party. He puts everyone else to sleep first, except Alonso, Sebastian, and Antonio.
Alonso is surprised to see this.
What, all so soon asleep? I wish mine eyes
Would, with themselves, shut up my thoughts: I find
They are inclined to do so. (Act 2, Scene 1)
Deeply troubled by grief, Alonso wants to sleep. He finds it a comfort. In sleep he can forget about his son, whom he lost so recently. Sebastian and Antonio offer to guard him so that he can sleep. To this he responds, “Thank you. Wondrous heavy” because he is falling asleep.
When he is asleep, they consider killing him, but Ariel interrupts the whole thing just as their swords are drawn. She knows Propero has plans for all of them, including Alonso, and will not want him dead. They pretend they saw danger and were defending him.
Alonso’s grief at his son’s “death” likely contains some guilt for what he has done to Prospero. He aided Antonio in taking the kingdom from his brother, but Antonio was the bigger villain in the affair. He is the one who betrayed his own brother. Fortunately for Alonso, Ferdinand is not really dead! Prospero also eventually forgives him. He forgives all of them, but he does take his kingdom back!