How do you figure? They seem phonetically similar because both Somali and Arabic are Afro-Asiatic languages. We already use khayr in daily speech, and incorporated Arabic words are almost always equal to the original Arabic word.
I also use the word sugar and safari in English. The origins of both these words are well-attested.
I know they are both Afro-Asiatic languages, but on different ends of the spectrum (Arabic is a not Cushitic language). It could be an original word, but I thought it was interesting coincidence. I only assume it is one because, as I said, because I did coursework in college and Somali speakers did gloss examples for us and I was surprised at how Arabic-heavy some vocab was. This does not make me an expert on the topic, and I would admit I know not enough of Somali to say anything definitive.
I just wrote what came to my head. Somali is very interesting to me, but I could not find any good etymology resources online.
