Well, I don't think it'll end up on the Daily Mail. It's actually really common for men to use sex toys http://www.girlonthenet.com/2014/09/24/male-sex-toys-popular/. As for Facebook, your sisters would need to have a giggly-ashamed attitude towards sex and also want to humiliate you, in a way that could backfire onto them, and hopefully they are nothing like that. Which doesn't mean that you want to discuss your sex life in depth with them, of course, but chances are they would be discreet if they did find out. I'm disabled and have support workers coming in four days a week, and I do sometimes fret that they will get into my sex toy drawer by mistake when hunting for a box of medication or the toenail scissors or what have you. But thankfully I have nice friendly support workers who are grownups about this sort of thing, and I've even had the odd discussion of sex toys with one of them, so I think they'd just close the drawer and move on. I can't speak for what it's like having sisters as I don't have siblings, although thank heaven you're not having to deal with this with parents, but if they grew up with you being a happily sexually active teenager, I don't think this will shock them.
A depressing number of people think that disabled folk shouldn't have a sexuality. One of the reasons why I prefer to go to the Sexual Health Centre for anything gynaecological rather than my GP is that I've had the odd GP give me very funny looks for trying to discuss medical issues affecting my sex life. I still remember explaining that I wasn't wild about being on tramadol for pain relief because it makes it near impossible to orgasm, and then having to repeat myself because I was getting a "does not compute" reaction from the GP.
Anyway, I found that there is a lot of social stigma to work through, you can't help but internalise some of it, and it took me quite a while to do that. I ended up writing a guest blog for Girl on the Net about disability and sex which says a lot of what I was going to say here, so here it is: http://www.girlonthenet.com/2015/01/30/reclaiming-wheelchair-sexy-lift-snogs/. She's also published this guest blog on kinky sex and disability: http://www.girlonthenet.com/2014/11/21/sex-and-disability-kinky-sex/. I know quite a few kinky folk who are also disabled.
In other words, yes, you can continue to be a sexual being even after being hit by disability! Very much so! It's still early days for you, it takes a hell of a long time to adjust, and it must have been horrendous losing your brother too. It's natural for your sex drive to be lower for a while after that sort of experience, especially if you've been internalising any of the shame that disabled people have thrown at them. You'll get there, you'll get your head around the changes, your confidence and sex drive will improve again, and your sisters sound like lovely, supportive women. Get yourself some fabulous sex toys, and if you're worried that you'll be single forever, don't be. There are loads of us who are disabled and have loving partners and great sex lives. I expected that everyone would ignore me when I started online dating, I mean I'm severely disabled and can't work, but I met plenty of friendly folks before meeting my partner.