I'm sorry for the recent passing of Mishka's mate.
I can tell you that the budgie in the photo is not 10 weeks old, he is much older.
His irises are already fully developed, he has clearly gone through his first moult.
Looking at him, I'd say he is at the very least close to reaching one year old.
Due to his colour mutation/genes, the colour on his cere has retained the immature colour.
The noise you mention, is it sneezing?
If your budgie has laboured breathing and you notice a pronounced tail bob and he keeps on sneezing/making the sniffling noise as you say, then it would really be best to have your budgie seen by an avian vet specialist.
Be sure to practice quarantine procedures during this time: https://talkbudgies.com/new-budgie-ar...necessary.html