All of the concerns you expressed, some of which are echoed by your friend's testimony as to his needs being disregarded at a hospital, have and will occur whether or not workers are unionized, as long as disabled persons in particular and patients in general are not regarded as sources of knowledge. Solving this problem requires the organizing of disabled people and solidarity of others, on which you have been working. Some of your comments suggest that you think of home care workers' unionization as a debit for those who are given care, in the zero-sum game of power.
Your insistence that it is important that disabled persons be empowered to fire an attendant on the spot, that there be no-strike clause, etc. is understandable but seems to me to be counter-productive. You yourself say that homecare work is one of the last-resort jobs, so workers who take this kind of job "tend to be people who can't get work doing anything else," to quote from your reply. Unionization should make this line of work more attractive and give workers a reason to want to stick to it. If a job is unpleasant and pays little, there are not many incentives to do it well, especially given that taking care of a disabled and/or old person is tough enough work even if it pays well.
A strike isn't the only reason that workers may cause an inconvenience for disabled persons. They can quit, may not show up when they are supposed to, may be late or go home early, may work to rule or do even less than that, etc. Such situations are likely to occur more often when workers are dissatisfied with their jobs in some way. If you think that unorganized ways of expressing discontent are preferable to organized ones, you may insist upon a no-strike clause, but otherwise, what's the advantage for the disabled? (And why should a strike be a 'public relations disaster' for workers, and not the state? A strike can be prevented if the state makes concessions.)
Do you think it is a good idea to empower patients so that they can fire a doctor, a nurse, an orderly, etc. on the spot? Maybe you do, but if you don't think that's a good idea, why should home care attendants be let go on the spot if those who are given their care think fit?
Yoshie