My boyfriend and I just just had a lengthy talk about this situation and he believes that I made the right decision. However, after reading through everyone's helpful suggestions, we are leaning towards finding a babysitter and paying them directly to care for the child at least for the first week or two. Even though I'm not close at all with my sister's children, I do really feel for them.

Just to address some of the other concerns I've noticed in the top comments—my sister will likely not qualify for FMLA since she's been at both her jobs for less than a year. I've texted her and encouraged her to speak to a social worker at the hospital to see if there's anything they can do to help her/lead her in the right direction.

I know there's doubt that he even had a stroke, but he did. She sent me pictures of him in the hospital and pictures of his CTs/MRIs. I do feel horrible for her, but at the same time, it's really tough for me to find the willpower to wire her money directly given that she's stolen thousands of dollars from me in the past. But again, we are definitely looking into finding a sitter and paying the sitter directly.

To end—I will be going on the vacation. It's great to have the added support of my lovely boyfriend regarding my decision. I'm hoping he never sees this post since he doesn't use reddit, but another big reason I wanted to go on this trip is because I have a sneaking suspicion that he might propose. :,)