OK, and what formats can your lawyer use? Email knows about attachments and it knows about forwarding a single message in-line. Neither method is capable of processing a nested structure such as a folder. You could add the messages as attachments to a new message by drag-and-drop, but you need to be aware of the cumulative size of the message+attachments and check it's below limits set by your own email provider or ISP, and also of a size permitted by your correspondent's email service. Alternatively…having checked what the lawyer can work with, I'd export the folder contents (probably to .eml files for fidelity), zip them up and hand over the zip file, possibly as an attachment to an email message. Just about anything else you do with them will probably change their headers and may degrade their value for forensic purposes.