Military Trainer
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 12.5
Situational Awareness; Confusion
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter VFR In IMC
Procedure; Weather; Human Factors
I was on CIC and another CPC (Certified Professional Controller) was conducting OJT with a trainee.  The trainee had two aircraft on a STAR; the one in back climbing out of 065 for 080.  Aircraft X; a [military] flight of 4 checked on inbound to GGG IFR.  The developmental issued descent to 090 and told them about traffic.  In my opinion; the altitude cap was unnecessary; but kept the flight above the aircraft climbing.  Aircraft X was looking to enter the VFR pattern at GGG via the overhead/break.  They didn't like being capped; so they cancelled IFR and were acknowledged; but still kept at or above 090.  They asked for a vector to avoid buildups to the East and the developmental issued HDG 050.  They then said that they couldn't maintain VFR on that heading and said 'We're IFR at 090.'  The developmental said roger; but never re-cleared them IFR.  He then issued a heading 360 and a descent.  This put Aircraft X on a converging course with Aircraft Y.  Aircraft X and flight lost the 4NM IFR separation with the overflight; but there was some question as to whether they were still IFR or not since they'd never been re-cleared.  The OJT Instructor should have taken over sooner and put a less complicated plan into effect.
GGG TRACON Controller reports of a loss of separation due to a flight of aircraft that deviated due to weather.  The flight had previously cancelled IFR; but could not maintain VFR due to the weather.