I buy some of this, I doubt both engines would flame out though. If he did not have structural failure, it's apparent he over banked and spun in. Even if he got into the lead's wake turbulence, it should have not tossed him around to an extent where he couldn't control the aircraft (Su25 T/O weight should be about 40,000 pounds so we're not talking small aircraft here).
There does seem to be something coming off the left wing. The Su25 does have speedbrakes at the wing tip IIRC. I'm wondering if that's the point of failure
The only other thing to took at is if he shelled an engine (compressor or turbine blew) and that resulted in taking out flight controls. I know these aircraft have a lot of armor around the engines to prevent this, but you can always have that one piece of engine shrapnel that got lucky.