Had a look at the Harvard option and it looks like you need to attend some of the courses on site as part of earning the degree, so it's not 100% online if I read it correctly.
There's also been reports that Athabasca U is having funding issues at present, for those looking at this option (which is the only option in Canada for online in this field that I've found.)
I think the treatment will generalise better to other genetic diseases than to other brain diseases, let alone a brain disease like Alzheimer for which the cause is badly understood.
Depends on what you're trying to do. Myself I've been in the IT industry since 1999 and have been mostly successful with a High School diploma. If you don't plan to move outside your country, I've found you can make a career out of it.
Met a few people from CHOP a few years ago during a conference, made me wish I could work in the US as I was pretty impressed by both the staff and the place