How long does it take for a dead cats eyes to go white and pop out?

Sorry for this rather disturbing question.

I have lost my beautiful tabby.
He went missing 4 days ago and my neighbor said she saw a dead cat just down the hill from my house.
She took a photo for me – as she knew I was looking for him.

This cat was black – but it had been raining – he had white markings on his legs and my tabby has.
The eyes were white and bulbous – popped out – not entirely but definitely popped.

The tail was only bone and one of the ears had been eaten of.
I have no way to identify him as when I went looking – he wasn’t there and I’m assuming the council would have taken him as they take dead animals.

I’m beside myself as I loved my cat so much.
I don’t want to look at the photo again as currently it’s haunting me seeing this decomposing creature that could my cat.

My cat was a grey tabby, with black and white markings.
Could it start to decompose in 3 days?

The mouth was open the tongue was out and white – or pale pink almost white.

Sorry for this question but I’m really wanting closure and I can’t find it – so thought maybe someone here might know if this can happen in under 4 days.

Thank you.
I hope this doesn’t disturb anyone.