Can I send a parcel from Germany to the USA if I only got the PO Box?

It's supposed to be a surprise and I don't want to ask the recipient for his actual address, although his wife might pick up the phone and get it wrong. But I'm worried he won't get my parcel this way. Is a PO Box only for small letters? The parcel is very light though, just some chocolate and a stuffed animal. Should I just try to send it?