I agree with Deb 100%, I've raised two runts in that range but both absorbed their yolk 100%. They still needed for me to assist them a few time's to get started.
The key with assist feeding is making sure the prey is small if it's to big it will be a long and stressful process.
A peach fuzzy mouse should do the trick. When you put it in it's mouth make sure the head of the mouse is all the way back and partially into the throat of your Bp.
Then you carefully close your Bp's mouth on the mouse and gently pull a little as to make the mouse really get caught into it's teeth. After you do this he won't be able to get this mouse outta his mouth, instincts kick in it will start taking it down.
Let's us know how it goes.