Imo, there are a number of layers to peel away (no pun intended). First, obviously, that the sex workers involved should be entirely willing to engage in this kind of activity. That may seem like a no-brainer, but very large numbers of "sex workers" have been trafficked, enslaved, brutalised, or at the very least did not freely choose to be "sex workers". It's a perfectly defensible point of view that, in fact, all sex workers were forced by circumstances aka poverty into their profession. It's also a defensible point of view that modelling for pornography or practising prostitution are irremediably demeaning, dehumanising activities for those who carry them out.

If you hold those sorts of views then I imagine you're bound to respond negatively to the proposals above. Which leaves you with the conclusion that masturbation and sex gadgetry is all the disabled will get, unless there's a mass volunteer movement of non-professionals who are willing to give more than a free hug. It's a painful dilemma -- this father seems to be right there in the difficulty of it:

I have a hard time seeing professionally provided sexual services as a replacement for skin and closeness

The word "love" is not pronounced (as a cheap euphemism for sex, fortunately, but unfortunately not seriously either). Thinking about it reminded me suddenly of something I saw quite often years ago. A group of twenty-or-so men, mostly with Downs syndrome, walking from the home where they were kept shuttered away (this really was some years back) to the village church, their only outing each week. Walking two-by-two, a half-mile along a lane. Orderly and quiet, yet many of the twos in fact couples, tenderly holding hands. Some in the village complained, but the curate OK'd it. What else could they do? he said. That seemed to show commendable open-mindedness, yet at the same time those men were shut away out of sight and a kind of condescending unction of the Church smothered the reality of their sexuality. Better to be nice about it than have it get nasty and leap at your face..?

I'm not going to get any conclusion out of that, am I? I'll leave it to you and others.