A few health questions

Hello!

I have a 5 week old indian ringneck parrot and I keep him at night in a tall box with sawdust from the pet store at the bottom of it.

I recently saw that he is nibbling the sawdust, maybe even swallowing small pieces of it in the process, and I wanted to ask you if this would affect him...

Other than that, I took him from a breeder a week ago which told me to feed him twice a day 30ml baby bird mix each time.

Yesterday I took him to a vet because he sneezed a few times (max 6 times in a day) and wanted to make sure that he isn't sick. The vet told me that he is fine (listened to his chest, which wasn't buzzing) and he put a small drop of deparasitation formula on the back of his neck and gave me some antibiotics "just to make sure" that he will be well in the following days. They need to be mixed with the formula as I understood, but I wanted to ask you first if any of you have had these experiences (with the sawdust eating, feeding twice a day those huge doses - instead of 3 or 4 smaller ones - sneezing without any apparent reason and antibiotics without him being actually sick).

Thanks for your time and hope to hear from you soon!

Miai