This just happened today and I'm distressed. My cat died and I need honest opinions on whether I was an asshole that contributed to this or whether I'm being irrational in grief.

So my cat is about 7 years old. He lived with me at my dads place and when I moved out a few years ago, I ended up having him stay there. I cant stay at my dads, because the house triggers my asthma/allergies, but that's because I'm particularly  sensitive. 

This has been a sore spot for me, because my dad and family aren't the most responsible. They will feed/clean litter/pet him/give him treats but they're not on top of his health. However, I live in a studio (basically a room) and every time I bring my cat over, he pretty much just sits on a bed and is by himself most of the day. So I've felt that having a whole house to roam and constant attention is a better living situation for him, with me taking him to vet visits and so on.

A few months ago, I realized it had been a couple years since his last checkup and brought him to the vet. He was overweight but otherwise in perfect health. However, he had a dental condition that the vet said could be causing pain while eating, and they recommended dental cleaning under anesthesia and tooth extraction,  possibly up to his full mouth. 

This seemed extreme and the anesthesia seemed risky to me, and since the vet was small, I decided I would delay the decision for a few months and go for a second opinion with a more advanced vet when my parents were both on vacation and I'd have him at my place anyway. This way, I'd have time to think things over and if he needed the tooth extraction, I could handle the post-op care and make sure it was handled properly.

Fast forward to this Monday, my dad has left and I'm going to pick my cat up on Tuesday and bring him to the vet on Wednesday. 

Monday night, my girlfriend ended up improperly using Drano and bursting a pipe, flooding my kitchen with Drano water. This was then tracked through the apartment. I was extremely concerned, because Drano is severely caustic/toxic, and I do not want my cat getting any residue on his paws and becoming sick. My apartment is one room, so there's no way to block off areas either.

So I decided I would go by my dads to feed him until I could have my apartment cleaned properly. Tuesday, I went by and fed him. 

Wednesday, when it seemed like the cleaning would take longer than expected, I messaged my mom and arranged to take him to her place, where I'd stay with him. 

That night, I took him to the vet. It was -5 Celcius out - I drove the 10 minute drive there, but theres 5 minutes in the car where it's cold (need to wait to turn on heating) and 3 minutes walk from the parking spot. 

At the vets, hes fine. Still in great health. I ask a bunch of questions about the dental treatment and am confident in the vet's answers, so we tentatively plan for a cleaning in two weeks. 

We leave the vet- again, maybe 8 - 10 minutes combined low temperature between the walk and the car heating up. 

When we get to my dads, he's peed in the carrier, so I take him to the washroom, run a bath and then bathe him in lukewarm water. I use tearless baby shampoo from a new bottle, which is safe for use on cats. 

After, I used a small towel to wipe some of the water off him but he was still pretty wet. He was frazzled and wanted to run from the bathroom, so I let him go. Then, I took another small towel, found him and wiped him down again. He was still a bit damp but I figured he'd air dry. The house is warm too. I left some treats for him and left. 

Today, I went to go pick him up to take to my moms. I pack his things and then when I go look for him, hes dead and stiff as a board. 

He was in perfect health. All I can think is...I killed him. He must gave got hypothermia. I would never imagine that some brief outside temperature and a bath would kill a large cat, but it's the only option I see besides a heart attack. He used to be a stray and lived outdoors during rain storms - I cant believe he'd die from this.

I don't know if I'm being too hard on myself or if I murdered him. I'm devastated - I'm taking him for a necropsy tomorrow. 

If he had a heart attack from the stress, I'll feel a little less guilty, because I can't not take him to the vet, but there were no indications of heart disease.