"We came home that same night when he met Siggy for the first time," Kirsty Jai Skelton told Love Meow. "Siggy sniffed him, rubbed his head and fell asleep next to us."

"Isaac turned out to be seriously ill with multiple heart problems (he's just had his first open heart surgery at 12 weeks old) and I think Siggy knew because he would sleep under Isaac's moses basket whenever Isaac was in it, like he was guarding him."

Siggy loved Isaac right from the beginning, like a protective older brother. He would purr constantly around him.

"Isaac went into hospital for over a month when he was 3 weeks old and Siggy went to stay with a friend, and when we came home and fetched him he was doting on Isaac."Isaac has since returned home and is doing great! "He makes me so proud, he's always been the happiest, most affectionate baby. He's not let it keep him down!" Skelton said.

Isaac's parents truly believe that the unconditional love and attention Siggy provided helped their son through his battle.It's amazing how cats and dogs can sense when their humans are not feeling well.