If the 5 year old boy will wear diapers for the bed wetting then yes the 5 year old should wear diapers for bed wetting.
There's no set age limit that you cannot wear diapers and if a 5 year old boy needs diapers at night then they should wear them.
Even if a 5 year old boy or any age needs diapers during the day they should wear them and there's nothing wrong with it.
A 5 year old boy should be able to fit into a size 7 diaper if they are skinny enough but if they are not that skinny then you may need to buy Youth disposable diapers.
Don't force the 5 year old to wear diapers but give them that option.
If not then just put a mattress protector on the child's bed.
Kids who wet the bed at night should wear diapers at night to keep their bed dry and their clothing dry as well.
So you should tell them that they need to wear diapers for the bed wetting and that you will keep it between you and not tell anyone else about it.
Most kids will be reluctant to want to wear diapers for bed wetting so don't force them to wear the diapers if they don't want too.
But give them the option and they may eventually decide to wear the diapers.
My kids wore diapers for bed wetting and they took too it pretty easily but some may not.
If the kid is only wetting the bed then the diapers are only needed at night and not during the day.
So no don't make the kids wear the diapers during the day if they don't need them.
If a child is wetting the bed at night and wearing diapers for the bed wetting then the child should remain sleeping in the diaper until they are dry through the night.
There are no age limits for diapers and once you have your child used to wearing diapers at night then they should continue to wear the diapers until they keep the diaper dry at night.
That could mean that if the child is wetting the bed at 8 years old and 10 years old then they should continue wearing diapers.
You can buy youth sized disposable diapers online once the child outgrows the baby diapers and regular diapers work much better than pull ups do.
Then when they get older and outgrow the youth diapers you can buy adult disposable diapers online.
Only have the child or teen stop wearing diapers at night when they wake up in the morning with a dry diaper.
It's much better for the child or teen to wear a diaper to bed and pee in the diaper than it would be to wake up in a wet bed.
I used to wet the bed as a kid and I wished I had diapers because I woke up every morning in a soaking wet bed and soaking wet clothes and that was miserable.
The diaper would've been much better.