My husband is putting baseboard up and doesn't know if he can use brad nails into the drywall. Help please!

I do a lot of finished carpentry for fun! He should get a studfinder to locate the studs behind the drywall/plaster walls. I would recommend at least 2" finish nails...half inch of drywall...roughly half inch of baseboard...plus you want it to go into the studs about an inch or more. If he is going to add a 3/4 inch quarter round molding after the baseboard molding, then he should probably use 1 1/2" finish nails for this purpose.

He should be able to see the screws or nails for the drywall or see the studs. He really needs to hit the studs or the baseboard could fall off or just release a bit from the drywall and look bad. 1-1/4" brads should work fine.

brad nails are going to be too short to hit anything other than drywall. use 6d finish nails

nail threw the drywall into the studs