Hi hope someone can steer me in the right direction here.

My bf was is a non US citizen who married in Missouri two years ago. His wife walked out one month after they married and never contacted him. He spent the last eight months trying to find her with PI's . She is in Missouri and he filed for divorce. He does not live in the US as he never filed for residency given the circumstances and returned to his home country.His lawyer has been most unhelpful in keeping him updated. The wife has been served with papers but there has been no response. Now the lawyer is saying that my bf must return to Missouri from overseas to be in court as Missouri laws say that one of them must attend.
This seems very odd to me. He has asked if the lawyer could attend on his behalf but was told no. Is this truly a Missouri divorce law?