Why? I’m following the Reddit convention of replying before I watch the video, but even if you don’t have someone who can speak sign language,

• a lot can be communicated by gestures and touch
• surely the flight attendant has or can get an effing smartphone to type or translate

Edit:

• she noted on the ticket she was deaf; flight attendants shouldn’t be surprised

Even if that story is bs and the airline’s story about an open container is true

• they’re not claiming she was visibly drunk
• we’ve all done that - sucked down our drink so we don’t waste it, even if it’s just water, while complying with open container restrictions
• reads like an excuse, especially with the detail about the gate agent