When addressing anyone by letter or introduction the man is first and then his partner. The only exception with an introduction face to face is if the woman is your friend (Example: This is my friend Jane Doe and her husband Jack.)
* Informally means casual so you would address a husband and wife by their first names. Formally is when you would use Mr. Doe or Mrs. Doe.
It is etiquette to put the wife's name first and inside the card put her name first and then the husbands (the deceased was his mother-in-law) so he should be included.
As Mr & Mrs.
You would use the first name of the husband and the first name of the wife. This is how you address a Japanese married couple through a letter.
the understanding of husband and wife is first given in Genesis 2:24
Mr & Mrs James Angstrom Jr.
The husband's name is listed first.
Major and Mrs . . .
When addressing a deceased husband's wife, it is respectful and compassionate to refer to her as the widow or the late husband's wife. It is important to offer condolences and show empathy towards her loss.
Dr. Mary Smith and Mr. James Doe
Just address the card to Mr and Mrs (husband's name). It's perfectly okay to address the husband and wife but to avoid offending the wife just do the Mr and Ms last name and you're probably safe.
Confront the husband first, then talk to the wife if the husband doesn't stop.