Tiny had that wasting disease, and he finally succumbed to it. He died a couple of days ago. Although sad we have to think of his buddy Gizmo. He is looking depressed and lonely. I hate to get another guinea pig so soon, but my daughter is scared for her little piggy, and wants him to have a pal.
Hi
I am ever so sorry for your loss.
Guinea pigs mourn no less deeply as humans although most will pick up their life again after a few days, if without their sparkle. As long as Gizmo is still eating and drinking, you have around 1-4 weeks ideally to look for a new friend for him. This time span allows you to get hopefully over the roughest bit yourself.
Only guinea pigs that have stopped eating and drinking and are giving up on life (acute pining) need company asap - thankfully this is pretty rare.
You may find the information and practical tips in this link here helpful to support Gizmo during this time:
Looking After A Bereaved Guinea Pig
Our human grieving guide does have a chapter on resources for children if that would help you:
Human Bereavement: Grieving, Coping and Support Links for Guinea Pig Owners and Their Children
You can find some helpful information on finding a suitable friend and minimise the risks of a personality clash (especially when you haven't got access to a rescue that offers dating for single guinea pigs to achieve character compatibility and acceptance before you bring a new companion home). Please take the time to do your research.
Single Guinea Pigs - Challenges and Responsibilities (contains a chapter on the specific challenges with single guinea pigs, finding new company and how to spot when a single is becoming depressed and starved for company of their own kind)
A Comprehensive Guide to Guinea Pig Boars (contains a helpful chapter on companionship with a boar specific slant)
Rescues, Shops, Breeders or Online? - What to consider when getting guinea pigs
Unfortunately, the one guinea pig rescue in your state (Piggie Poo) has closed down a few years ago.
I hope that this will help you with both Gizmo and your daughter. Sitting by a grieving piggy is hard but he needs that time as humans need time to grieve on their own; he will be ready for new company when he picks up his normal life again.