Sharing the Communion

I was serving communion one Sunday. The communion was by serving a piece of bread and a small cup of grape juice. Each parishioner falls in line to receive the eucharist. However, some mothers carrying an infant and the elderly who could not walk remain in their seat and wait to be served. So after serving communion to those able to fall in line, I started walking towards those who remain seated. I first offered to a 90 year very old man who I believe could not even swallow his saliva as I can see him salivating. He took a very small piece of bread, ate it and swallowed it fast. He then took the small cup, and with some difficulty, sipped just a little that it was still more than half full. Usually, after drinking the cup, they just hold on to it or put it in the back of pews. But I was surprised when the old man returned the small cup, still with his saliva lining the rim of the cup, back in my serving plate . Then I moved to the next person, a sophisticated young woman holding a baby. This lady was known for being so fussy. Anyway, she also took a very small piece of bread and ate it with style and poise. Then she took the small cup and drank all of it. Before she could finish the cup I realized that it was the same small cup that the old man had put back in my plate. Oh no! I said to myself... I don't know if I would laugh, or feel bad, or what... It was too late now...