My friend has a problem redeeming a 3 month gold prepaid card

Time you redeem via prepaid cards is fully added to whatever time is left on your son's account (up to 36 months).

So for example if your son has still 3 months of Gold left on his account, and you add a 12 month card, your son has 15 months of gold on his account.

Or if your son has an active subscription, and his subscription would renew in 3 months from now, and you add the 12 month card, the prepaid card will "pause" his subscription, activate 12 months, and after the 12 months of the card are over, the subscription
will continue with the remaining 3 months, and your son will have to be billed again in 15 months from now.

So there really is no need to wait until you redeem prepaid cards.

In fact, since some promotional cards have an expiry date on them, I heartily recommend to redeem prepaid cards as soon as possible.

But keep in mind, that you can have only up to 36 month of Gold or Game Pass time on your account.

Ok,i got it,he said he gets to the screen where it says if he wants to redeem his code and,when he hits yes,it says something like missing content,please help us.

it might be he has not yet added his billing Information, just navigate to Settings -> account -> 2steps to right -> billing Information -> make sure they are correct and complete.

if it still wont work, is there any error code shown?

then check it on
support.xbox.com/error-code-lookup

i bought my xbox and received a 2 prepaid gold cards ad i redeemed the 6 month card i have the same problem as acetothekitten but those the prepaid gold cards count as a free membership? if so then why those the xbox come with a gold code??

Hello, EpicSpiderman7! Unfortunately, at this time, there is no way to pause or suspend your Gold membership. Once you redeem the prepaid card, the time starts. My only suggestion to you is to get a 3-month prepaid and save that 12-month until you get
back.