SNUG by Michael morpurgo

Snug the cat arrives at the family home just before Lisa is born, and the two grow up practically inseparable. However, as Snug transitions into a tomcat, his independent nature pulls him away for longer stretches of time. One night, he returns home severely beaten up. The story takes young readers on an emotional rollercoaster as they learn about the delicate balance of giving pets their freedom while maintaining a deep friendship with them. [1, 2, 3, 4]