I am so sorry to hear about Barney
A terrible thing to happen and especially to a cat so young.
Do you have any idea where he may have had access to this?
Feeding both wet and dry food is better for cats but would have had no effect on what happened, dont beat yourself up its not your fault
It must be very hard having to tell everyone what happened but has to be said its just a plain hard thing and you have to grieve yourself which I can underrstand is hard for you. I think children are more accepting and maybe when young get over things quicker.
I think a new cat will be good for all of you but you will need to monitor carefully and dont rush this, after Chrissy sounds like a possible good time. One can never rule out accidents but if someone is deliberately poisoning cats in your area then the police need to have it on record so they can build up a profile. It maybe worth ringing them and asking if any other cats have been reported as being poisoned and ask them to put this on a report and ASK FOR THE NUMBER.
I will put Barney on our Roll of Hounour for the next year,,,,,,,,,they are published mid-Nov on Purrs birthday
RIP Barney taken too young