I've always got something that can murder him equipped because I never leave myself without a good melee option.and honestly at this point I don't even bother with defenses.but I also tend to have a combo that interferes with his ability to have a good if you can give us a rundown of your options I bet we could help! If not and you're really hurting for melee, I've got loads of duplicate stances that turn underused melee weapons into absolute beasts, it's not like I can use them twice or anything, right? Feel free to give me a yell in-game or PM me here if it's still a struggle.
I don't do anything terribly unique, I tend to go with attack speed and range but range really isn't a factor here, and I've done it with the Obex, Lecta, Lacera, Mios, Tipedo, and probably a few other weapons.
Given how chaotic combat tends to be that's generally my approach, get right up in his gob and don't bother with angry words or pretty techniques. He doesn't seem to be terribly strong to fists/swords/sticks/daggers to the face.