No one knows for sure. Judging from the last scenes in
Pusher (1996), it seems quite clear that Frank doesn't survive. However, one can assume that he may still be alive having fled Copenhagen because Milo asks Tonny if he has seen Frank around, signifying that Milo did not find Frank as of yet. On the other side Milo's question could be an attempt to hide that he is responsible for Frank's dead.