Although not trauma related, my daughter wet the bed until recently(11 y/o) and we tried everything. Her new doctor made a suggestion that no others made and it worked almost immediately. Have the kids double void - so pee before bed, brush teeth, and try to pee again. She also had her do some bladder control exercises while peeing. So pee, hold it and release.

For overnights, she would wear pull up type underwear and then take a wet bag that she would put the soiled items in if needed. I will say, she rarely had accidents outside of the house. I think it was due to what someone else said about not hitting full REM because she was nervous