TL;DR My brother-in-law's (25M) fiancée (25F) has been MIA for the last 4 weeks of his chemotherapy despite living only 2 hours away and having both the means and the funds to visit him.

He was diagnosed with cancer a few weeks ago. At the time, I was really glad that he had my soon-to-be-sister-in-law in his life. I used to think of her as kind, attentive, responsible, trustworthy, reliable, etc. She still was all those things before the chemo started. However, things went south real quick after the first week of chemo. That first week hit us all much harder than we expected. My bother-in-law lost his hair quickly and had barely enough energy to walk to the garden. He moved back in with my in-laws, his parents, so that they could lend a helping hand. We've visited him each weekend and taken turns to visit him during the week. We try and keep his mind off the cancer but he's not interested in PlayStation or movies so we end up sitting in silence. I'm relatively certain that he's depressed which is not at all unexpected.

We've not seen her for more than 4 weeks now. This includes a brief period where he had to be admitted due to lack of immunity. Initially we thought that she might not have the money for the drive and offered to pay for her gas. She declined stating that her job needs her. Not to be rube, but she works as a teacher's assistant who on weekends sometimes needs to supervise the kids on field trips. She is not even primarily responsible for the kids and I'm assuming that she's easily replaceable. She obviously doesn't get paid much but her parents are reasonably well off. We've paid for things for her previously before the cancer and, like I've said, we offered to do so again this time.

As I'm writing this I'm thinking that she must just be overwhelmed by the cancer and the chemo. Well, time to pull up your big-girl pants. I also reached out to her during that first week saying that I'm available to talk or to take her out for ice cream or whatever. She declined and, at the time, I thought that she didn't want to abandon him which clearly is not the case anymore.

Just to be clear, my parents-in-law are lovely people. My mother-in-law is not at all the overbearing kind and even went wedding dress shopping with her before the diagnosis. My father-in-law is the silent type although I get the impression that you could cry on his shoulder if you really needed to. My brother-in-law's personality has changed only slightly. He's obviously needy and slightly demanding but not to an extent where I feel that its not in keeping with his cancer.

At this stage I've lost all faith in this young women who doesn't seem to care anymore. Even if the diagnosis and treatment were scary, I would still expect her to be brave enough to show up. Even if she doesn't want to talk to me or his family I would hope that her family is at least being supportive towards her.

Why am I asking the opinion of faceless internet strangers? Well, frankly, mostly to check whether I'm being crazy or unreasonable. Also, perhaps there's an angle I'm not seeing here. Although, like I've said before, even is she does have something else going on I would still expect her to prioritise her soon-to-be-husband. I don't think she's the type to cheat but at this point I wouldn't be surprised.