I can understand being on a work trip, possibly not having a lot of time. It's also possible he doesn't have transportation. So, texting to say he's thinking about you is at least a positive thing. If he was out near you a lot, and never saw you, then yeah, that's rude.

My skewed perspective comes from my experience with my siblings. They regularly visit Utah, where I live (they're in AZ), but don't text or call at all.

My younger brother was dating a woman in Utah for 3 years, and never once in that time did he reach out. I sent a text to a family group a few weeks ago, with no response for several days, then he finally responded saying he was "traveling", the implication was it was for his work. It wasn't, he was 10 minutes from my house, in Provo, while visiting his son.

So, you're doing well with your siblings, from my skewed perspective.