Polibeth, please do not go to the ER unless you yourself need to be admitted. Exposing yourself to all the germs in that environment is the last thing you need. While I'm sorry that your H has hurt his knee, the likelihood of this injury killing him is minuscule (unless he gets a blood clot or something). In my area, there are orthopedic clinics that offer walk in appointments - basically orthopedic specific urgent care.

If he needs a ride, which maybe he does if it's his right knee, he should get an Uber/Lyft/taxi/friend.