Death of an old dog

Bonjour,
J'ai travaillé le résumé de cette histoire mais je ne sais pas s'il est juste et complet. Si vous pouviez m'aider. :-)
Merci d'avance.

The short story is telling about an old dog, Ibo. It’s the dog of Richard Gavin and Paulina, his wife. Richard has a child, Tobbie, and a dog since its first marriage with Grace.
Paulina is going to vet with Ibo and she sees fit to kill it because he’s too old. She asks the advice neither of Richard, nor of Tobbie. She makes believe that the dog is sick. When she returns at home, she says that she’s sad because the vet doesn’t give much hope. Richard accepts that with resignation because, for him, his dog is old, smelly, half-blind and so forth. He said that there isn’t any more hope. She pretends to believe again.
Suddenly, Richard is distracted by the absence from Ibo because it didn’t come to slobber over the Richard’s hand and to wag his stumpy tail. Paulina speaks quickly and hastily to mask the absence of Ibo. Richard recalls to his wife that Toddie will return from the boarding school and that it will be shocked by the absence of Ibo. Since the death of his mother, Grace, he shows very few signs of affection, even with his own father. The only things which interest it are its dog Ibo and the murders, the law reports.
Toddie will realize that she killed Ibo. Therefore he intends to kill Paulina with exhaust fumes in the garage and to lock the doors from outside. He says that he’s proud of what he did because Ibo is redeemed and she didn’t have to kill behind their backs.