Nope, I couldn't do it, my family has been way too good to me. No abuse, neglect, or anything like that from any of them, I couldn't live with myself. Besides, a million dollars sounds nice at first, but you can't do too much with it, and still have a comfortable life.
For a random person in the world, I still probably wouldn't do it, but I could consider it if I were in dire need of it.
Not for my family, no. If I got to choose, I would press it. Lots of people out there don't deserve to live. ... But then again, people could argue that I don't, either... So, if I got to choose who it would be, yes, I'd press it. But I'm not a good person.
This isn't a "classic moral dilemma". It's a sicker version of the button dilemma. However, in the real version someone who you don't know dies. That's what makes it a real dilemma.
Really, this isn't as much a question of "would you do it?" as "do you hate your family enough to do it?". Plus, unless you're part of some religious group who doesn't believe in protection where families have like 15 members, you're only going to make something like 5-7 million out of this at best. No sensible person or anyone who had a decent upbringing would do this.
And neither would I. Family are something you have to really hate beyond reason to ever even consider killing. No amount of money or riches in the world will replace them. No one will ever know you like they do. Once they're gone, you've lost a part of yourself.