yes its a negative case, especially when ur friend already got a wife.
what i can say is. age is just some numbers, what matters lie in the head. and for this situation its what lies in the heart.
tell ur friend this.
observe it, it might be just a crush, that normally goes away in a while.
i got 1 female friend, shes 20+ but married to a 40+ rich GM guy who owns a lotus and bmw.
and another, 20+ married to a 40+ airport clearner
whats this called? L.O.V.E i guessed
however i dun encourage ur friend to keep this going as he already got a wife.
for the young lady, shes still young and got a long way to go. im sure she will have plenty of chances BEING hooked by other guys.
but for the wife with her age, i assumed, very unlikely to get another one.
her wife prone to get hurt real deep for this, unless the wife is the screwed up kind. then i got noting to say.
wat matters lie in the head and heart when comes to these "4 letters" games.