Relationship Issue. What should they do?

My friend is in a relationship with a guy for last 8 years. They have had there ups and downs but they were doing fine till new year this year. They were planning to get married and their families met, post that meet there were a few issues within families. But the problems which can be sorted post that the guy is confused and has started reconsidering the relationship all together. He has now convinced himself that this relationship is not going to workout. He thinks that ending this is best for his family and his happiness. He is not saying its because of the family issues but insist on that we were not happy and we have a lot of issues. Girl on the other hand believes there are no major issues and this can 200% workout. He has stopped talking to my friend at emotional level. He is being very formal but at times he falls back and says yes this will work out. He seems to be really confused and does not discuss this with anyone. What should they do ?