Can you expand on that? How does a BLU solo exactly? What spells, gear, etc?
That linked video is a bit oudated but its still the same strategy. It was a first attempt so they are usually sloppy with a lot of improvements. You should have a decent hybrid evasion set, set mp drainkiss (my spell set was in the video but it was at Lv95.) and magic hammer if you really need it (I had meds but im sure its a lot easier now at 99.)
Only real major parts are to watch for terror as it can potentially last a while and for flight mode. When he is flying that is a good time to 2hr him and have a good skillchain combo lined up to drop him really fast. Otherwise you will need a decent fire resist/-MDT set so you don't lose too much MP. Magic barrier is also helpful.
Relic+2 hands are good to extend 2hr duration but general SC combo could be (make sure you wait a second or two between spells so they connect for SC.)
-whirl of rage > quadrastrike > gob rush > a spikes > QC > bloodrake. It might be a bit taxing to set all those spells so pick and choose, generally won't take that much power to rip him down. Make good use of sudden lunge too, especially when hes flying as it works there.