Can someone help my friend, please?

my friend's hu*****and wants to put all their properties ( cash, house, everything) in a trust, saying that that is the only way his wife can get everything after he dies. But the wife thinks: as long as they are hu*****and and wife, there is no need to put everything in a trust, because after one dies the other one will automatically inherite everything? can anyone please tell my friend who is right, who is wrong?