My family and other animal.

I'm mad on Cats. I love em, I really do.
As you know from reading my blog, my Dad has sold his little Hotel in Bournemouth to developers (it's going to be flattened) and they are moving (actually they've gone already) to Barton on Sea.
They are taking our cat (Inky) with them who has never known anywhere but the hotel. He's extremely Fat (coz my step mum feeds him lard and cheese) and nobody really loves him except me. Unfortunately, because of University and now living in a flat in Hampshire I don't get a chance to see him much.

My Mum has been really worried recently about my cat. She was under the strange impression that my dad would have him put down (to prevent this, she suggested inky go live with her).
Of course, I assured her that my Dad wouldn't do that (i'm not even sure a vet would do it).
I thought that would be the end of it, but she's mentioned it several times in the past couple of months and seems genuinely concerned. She said to Lisa, "you don't know grants dad like I do".

So my question is this, if it turns out that my cat Inky is no longer with us, how long should I refuse to talk to him. I'm thinking 5 years is a reasonable sentence.
Lisa said that this was probably harsh and that I should just not talk to him while I am still angry.
If that was the sentence, it would be a cold day in Hell before we would converse again.
Am I being unreasonable (after all, they feed and give Inky shelter- not me) or would he deserve a stiffer sentence?