Remember, it's not about you to him. It's about what he is feeling. He feels sad and depressed and like life is worthless. Just validate how sad that must feel and maybe share a time, not related to him, when you felt sad and that things were hopeless. You don't have to fix it without him asking for it. Maybe ask how you can help, but if he says there's nothing to be done, remember it's not personal or anything against you. He is depressed.

When someone is depressed like that, the simplest tasks can seem overwhelming and inconveniences turn into big issues.

He confuses me.  I validated and he acted like he had no idea what I was talking about.  It's almost as if he was acting like I was talking to someone else.  Doesn't surprise me though.  There have been times where he seems to lose fraction of times.  I would bring up things we had talked about and he got frustrated because he wouldn't know what I was talking about.  These times have me worry.  I remember thinking at the time that this person I am talking to isn't him. The look he gets in his eyes, his demeanor will change.  Some time when he really rages or is really low, it's like he's checked out, but still there.  He'll have conversations, but he feels different.  I pretty summed it up to BPD.  When he told me he has a fractured part of him that saved him from some really bad times of severe abuse.  I feel that this fractured part of him almost makes an appearance every now and then.  I can't otherwise explain the more than once gap in his memories.