Your deacon friend may very well partake of a small amount of wine and no bread (as you may very well know, this is how we commune infants).
And yes, it's my experience that the duty of consuming the chalice falls to the priest when a deacon is not present. My parish does not currently have a deacon, and so our priest consumes the chalice after every Liturgy. This is probably what your friend's priest does as well. Our local GOA parish also has no deacon. I assume that their priest also consumes the chalice.