My boyfriend pays his child support every week it is taken out of his check he in addition pays his arrears it is all in one lump sum I have 2 things to ask
If we were to have a joint checking account can child support seize the account and he is waiting to hear from ssdi because he has a blood disorder and if he gets approved I know the child will receive benefits but can they take what is owed in arrears too also can they take from a 401 k account...

Yes, if he is listed as the owner on an account it could be seized.

No they can't take from a 401(k).

Why would you have a joint checking account. You aren't even married. I didn't even have one when married. Alternate bill paying or something; it isn't hard. And there are tons of free no minimum checking accounts out there.