I have often seen my priest walk with the chalice to commune those who could not come to him.
I do think that there should be training at seminary for how to minister to the disabled. I think there might already be.
Many times, it's hard to tell if someone is disabled, and a priest might not know if someone is not making it to the chalice unless he is informed. A lot of times, I think, it is assumed that people have someone to take care of them, but that is not always the case. It is assumed the priest will make a visit, for example, but was a visit requested? I agree, there has to be initiative, but one must also advocate for oneself or for another person. It is, unfortunately, the same way in our health care system, and even with advocacy, they don't listen to you.