My Tenant gave a 30 day notice but he has 4 months left on his lease. He is moving out of the area tomorrow night. He emailed me this evening stating he wanted to do his "walk-through" tomorrow at 6:00 pm so he can get his deposit back and give me the keys. I think he's under the impression that I'm giving him his deposit refund on the spot. In Calif I'm required to do a pre-move out inspection if requested but he did not give me 48 hours notice of the date and time (which I think is intentional as a pressure tactic). I do not want a conflict with him in person. Should I say I am unable to meet at that time? What's the point of his pre-move out inspection when he has no way of repairing any damage (if there is any) when he is leaving the area tomorrow night?
Should I go at 6 pm and explain this is for a "pre-move out" inspection and I will do a final inspection later,  provide an accounting of his deposit and any applicable refund and mail it to them with in 21 days? Suggestions?

A pre-inspection is only to give the tenant a chance to remedy/fix any damages. You have 21 days from the day they move out and hand over the keys to return their deposit minus charges. You can do your final inspection with them as well but I recommend just doing it alone after they are gone.

Read your state laws and lease . He may not be entitled to his deposit back due to moving our 4 months early . They could be responsible for the rent until you re rent it or the 4 months is up