To what extent does TILL DEATH DO US PART go...?

had discussion with a co-worker.....his wife and mother DO NOT GET ALONG AT ALL...so he was wondering, if he should die who would have final say in his death .....his mother's argument is TILL DEATH DO US PART well the second he dies DEATH DID YOU PART and that she has the right to decide what, where, when, how to bury him not the wife for they are no longer married according to the vows they took....TILL DEATH DO US PART...his wife thinks it ends when he is buried/cremated...what are your thoughts???