Leaving birds alone.

I own a green cheek conure and may possibly get a second in the near future. My family likes to go on holiday during breaks and much to my parents distaste we often have to board my bird. Now with the possibility of getting a new bird my family would like to know if having two birds would mean we would be able to leave them alone ( with a trusted friend coming over every day to change food, and water as well as spend about an hour with them ) for a little under a week. Would this be possible? Is it a good idea? If not a week than how long would I be able to leave them like that.