Can a reform jew attend orthodox services?

I'm not a Jew, but I have a very good Jewish friend. Because He accepted Jesus, he was thrown out of his own family. They are very devoted to God, but, they don't believe Jesus was the Messiah. They're still waiting for Him. But now most of his family have accepted Jesus too. Still working on the rest. Won't they be surprised when the Messiah comes back and they think it's for the 1st time and we know it's for the 2nd time. WOW we're waiting on the same thing to happen..