Okay: on all the offense taken at the sexually charged joke:
Poster comes in to announce that she has seen a deaf guy at work that she is interested in. Knows virtually nothing about him, has not even been close enough to initiate a conversation to see if he reads lips. Has no idea how to communicate with him. Yet, she is "interested" in him. What else could it be at that point other than a physical attraction. I don't see the sexual joke as being that far off base, given the circumstances.
Of course, there is always the off chance that she just has some sort of morbid curiosity in the "disabled guy", but I prefer to give her the benefit of the doubt, lol.
To the OP: how do you know if he is sweet if you have never had a conversation with him? He could be a complete letch or a class A azzhole.