HUGS!
I am ever so sory that Crunchie hasn't made it! By the sound of it, you were really up against it despite doing all you could. Sadly, guinea pigs are very small animals and don't have the sheer body mass that can slow down illness. You are most welcome to post a tribute to Crunchie in our Rainbow Bridge section whenever you feel the time is right for you.
We have got a recommended good standard rescue locator on the top bar for our UK members. I can also provide contacts for rescues in the US, Canada and Australia. Most of the recommended rescues offer bonding at the rescue under expert supervision with their quarantined piggies, so you will only come home with a guaranteed healthy companion if there has been success and you do not have worry about ending up with two boys that won't get on. A rescue will also offer support for the whole lifetime of any of their piggies, so you are not left to deal with a mess on your own. You may find that a good age gap between two boars will strengthen the bond, as only one boar is going through the stroopy teenage hormones at any time. The key to any successful piggy bond is character compatibility; hence the dating - letting the piggies choose each other is crucial.
https://www.theguineapigforum.co.uk/pages/guinea-pig-rescue-locator/
https://www.theguineapigforum.co.uk/threads/looking-after-a-bereaved-piggy.110463/
As Crunchie has come down with URI in the end, I would strongly recommend to wait 2 weeks (the incubation period) before you do any intros, unless you get a piggy that has not undergone quarantine and will need to have one itself in a separate room. But the gap will hopefully give you time to look around and contact all rescues within your reach. Please note that many rescues don't advertise any single piggies that they keep for bonding with bereaved or fall-out piggies, so you will have to ring up or email and ask.
https://www.theguineapigforum.co.uk/threads/importance-of-quarantine.108034/
PS: With members from all over the world, we are very grateful if you added your country, state or or (for the UK) your county, so we can always give you the appropriate advice and recommendations straight away. Click on your username on the top bar, then go to personal details and scroll down to location. In the same section you can also upload your avatar, the picture that appears with every post you make. Thanks!