T-6 Instructor pilot reported G-Limit exceedance during windshear recovery and NMAC with lead aircraft.

Narrative

Flying forms home in two T-6B's as wing aircraft. Lead aircraft coordinated IFR clearance and we were on vectors to descend through ~2000 ft of clouds. While flying a wind advisory was in effect for mod/severe turbulence and low level windshear in the area; both pilots were unaware of the changes; winds were check prior to takeoff and nothing was reported for the area of operations we were working in. While we were flying in a tight parade through the clouds on radar vectors; my aircraft (wing) his a small pocket of air that blew us up and toward lead; who at the time was in a shallow left banking turn. As wing I lowered the nose a bit and reduced the power so as not to cross lead or continue to climb into them. I slid aft and nosed down the aircraft. During that time we entered an area of extremely dark clouds and were unable to see the lead aircraft. As PIC I went to lift my visor to better ascertain lead's position. We suddenly were hit by windshear; and the wind blew us to the right; taking us ~30 degrees off of our prior heading; while pushing the aircraft into a left bank angle exceeding 90 degrees; with a VSI of ~5000 fpm descent. I transitioned to an IMC scan and recognized the situation and immediately added power and rolled to wings level while keeping leveling the nose; reaching ~2200 ft MSL. I called lost sight to our lead aircraft with our current altitude and heading; and they had been unaffected by the winds so they were still on their gradual descent on the assigned vectored heading of 120. We further deconflicted our current positions and maintained 500 ft of vertical separation and coordinated with ATC separate squawks and new vectors for our aircraft. It was at that time that I conducted an OPS check and noticed that during the windshear recovery we had pulled 7.3 G's; exceeding our limit of 7. I elected to slow below 150 knots and remain below canned course rules altitude for any aircraft behind us and above us. We flew an uneventful visual straight in approach to a full stop at ZZZ.