Xu Jin could remain Li Ming's master and become brothers with the two geniuses of the Pine View because his own talents and strength were certainly not weak. After all, a genius and a fool can't play together; geniuses can only empathize with other geniuses, develop affinity with each other, and become companions.
If his strength wasn't sufficient, the sect wouldn't have assigned him to lead the power team that was sent to support Li Ming again.
Add to that, not to mention anything else, they had all just had a breakthrough and had entered the Innate Realm, already representing the extreme limit of combat power Li Ming could possess at the moment. With the three of them present, it was as if the team had an anchor that could maximize the entire team's safety guarantees.
When encountering masters of the Innate Realm, only the three of them could withstand the foes; under such circumstances, it was natural to prioritize enhancing their strength first.