How do I help my friend?

So today my friend came to me and told me that his gf and him that have been going out for almost 2 years broke up. They had almost the same ann. as my bf and me. and he told me they broke up because she cheated and she has been trying to get back together, but he wont and hes really upset and i just don’t know what to say because they are both my best friends and I’m just so confused. any ideas?