Ok when old lace died shouldn't chase have died to? I mean because of the link the feel each other's pain so if she died then he should've died to. When Gert died she gave up control because her dying would kill old lace too.

it looks as though he did die since he flatlined. 

He didn't gain total control over old lace, it seems, Old Lace DID still have some free-will and listened to Karolina during the Gibborim Arc in volume 2. Though Chase did flat line. I think he was fine after that, though, and then died at the end of issue 14. :(

They don't have a physical connection.

If Chase would have died when Old Lace died, that means that Old Lace did not really die. Which adds to the theory of Old Lace still being alive! Yes!

Exactly! 
All of it adds up now, there is just more 'evidence' now.