I realise this is not the best subreddit, but I just had a pet unexpectedly die and this is the only place I can think to ask for help.

I'm asking here because this community helped me the first time I had an unexpected loss, but things are a bit different as it's winter in New England, and last time it was in Florida.

I found him (pet rat, 1LB) an hour ago, like 3am. My mother won't let me put him in the freezer. It's like 7 degrees out there. He's in the hatchback of her car, in a box, in a Styrofoam cooler.

The plan is to get a pot and bury him in it, get a plant for him come spring. Put a stone over the soil for now to protect him from animals.

My question is, as everyone here was very kind and knowledgeable last time - in terms of decomp, will he be okay in the car for a few hours overnight? We'll have to go out and get the pot, so we'll probably leave him under a bush when we're gone. Tomorrow it'll be low 20s. Will he be okay in that temp? It's below freezing, so I imagine he would be? But I'm afraid he won't be, and it'll make things a lot more difficult emotionally and it'll feel like I disrespected him.

What will happen now that it's winter? I understand decomp will be slowed, but will there be any until spring? I'm afraid he'll be mummified. I'm sorry if I come off stupid. We can't afford cremation this time. Last time someone told me it'd just take a couple weeks for him to join with the soil - how long will it take now?

Thank you in advance. I'm sorry again for posting here. I can't think of another group that'd be as familiar with this sort of thing.