Sorry to hear about your loss hun. If you kept them together then you could try to bring another into the equation. I would wait for a little while first though because the sudden loss of a viv-mate is hard to realise.
An example in non-reptile nimals, we had our dog his whole life, and our cat was brought into the house when the dog was here, and they lived together with us for the best part of 16 years, then the dog died and for months later the cat was still searching for the dog. It's the same, regardless of how long they've been in together. If you give the remaining beardie time to understand what has happened, and remember to give it lots of attention and love, then if you still want to give company remember the quarantine the new animal in a viv of their own first.
A new animal can bring in other diseases and you'll also want to see for yourself that they're eating/drinking/pooping/shedding properly before putting them in with your other one. Then when you're sure both animals are healthy and happy you can introduce them in a neautral space - for example the settee, a bed, windowsill, anywhere other than the vivs they occupy. This is to reduce territorial confrontations.
I hope this helps you
