I'm so sorry to hear about your mom, Dominique.
Your family seems to be rammed with a bad luck wave at the moment. Hope all gets well and on track soon though.
You are currently on a "no win" situation, whatever you choose to do. If you stay and help your mom, you'll may be missing out on your future; however if you go, you'll feel guilty about leaving your mom when she needed you, and that may also compromise your concentration and chances for the future.
Maybe you should ask your mom if she wants you stay or not... thought she might just say "go" and mean "stay"...
Also, is going abroad something like "it's now or never!" or can it be postpone a couple a months or a year?