First of all, DJ won't be walking in there at 125lbs...
Secondly, we've already seen this multiple times before, Dustin rolled with Brian Shaw who weighs around 400lbs and handled himself quite well. The Mountain/Hafthor Bjornsson who also weighs around 400lbs has grappled/sparred with tiny MMA guys and didn't do too well either. But the number one thing with these giant meat factories is they GAS! Tren absolutely destroys your cardio.
If DJ is actually worried about this guy all he has to do is feint the single leg for 2 minutes and the guy will be too tired to fend off anything else and it's over, rear-naked 20 seconds later.