Book about cats

I can’t remember the name but there was an orange cat whose family brings home a little grey kitten he doesn’t like at first and he grows to a big fluffy grey cat then the orange cat dies and the grey cat is lonely so the family brings home a little Siamese kitten I believe who he doesn’t like at first then he remembers how the orange cat was patient with him. One if their names was Thomas I think. The last page shows the grey cat and little cat sleeping together with the orange cat above then watching them.