Despite having only Defense 2, his Endurance 5 forces the opponent to have to hurt him at least 3 times with common weapons that deal double damage, plus his Hardened allows him to convert him first blood of round into stun.
As far as equipment upgrades are concerned, since he is not a frontline character nor more useful beyond his 2 ammo, perhaps Street Guy ($50) is the improvement that suits him best as he can continue to have the bonus of crouch after coverage without sacrificing counters on it, so to run or move more would remain viable. Secondly, Magazine ($200) is always an improvement to be considered by the shooters of the team, but in the case of SoB 1 perhaps this only feasible if no other more powerful shooters are in the band and if funds are still available for it.
As far as his profile is concerned, both SoB 1 and 2 are exactly the same with Defense 2 and the combination of Endurance 5 with Hardened!, and in his case he doesn't need any equipment for being able to enhance his Pings! in -1 when crouching (Street Guy).
If SoB 2 was in the crew with other candidate for the sewers such as Carrie Kelley or SWAT Bravo, Sewer Map (1/E) can be a good strategy to put two of them in them at once, combining even with Maps (1/B) to have even more options to surprise the enemy from the rear and both leave together.
Regarding equipment upgrades that may be better for him, no doubt Extra Ammo ($200) for the Shotgun is almost a compulsory acquisition to take advantage as many times as you can with this weapon of mass control. Other improvements such as Flashlight ($100) or Whistle ($200) can come in handy because of his predisposition to use the sewers, but his Willpower 4 make combined use of getting out of the sewer, firing and using a whistle or lantern not possible.
Offensively speaking, although maintaining the same Attack value of 3 characteristically shared among all the S.O.B, he is equipped with Reinforced Gloves and has an above average strength of 4+, which means that 50 % of his impacts should hurt. Since his attacks are unarmed, this makes him an ideal candidate to grab enemies and then for his teammates to take out advantage, plus this normally will also result in a situation of Numerical Superiority. And not only that, as with all weapons of double damage, each of his successful wounds will result in the loss of a counter from his rival (plus any that have been invested to block the blows).
In defensive terms he has a base value up to many renowned personalities: 4, to which must be added his Counterattack. This in exchange for 1 SC gives him option to land a free hit for each impact during the rest of round; this is also resolved before the rivals successful impacts. So if SoB 3 left his opponent KO or Knocked Down the enemy attacks would not be resolved. In addition to this, like his brothers he has the security of Hardened, they’re a tough bunch these batsons! and 1 more point of Endurance than them at 6.
Finally, in Support/Control tasks SoB 3 is a henchman to take into account. First because he improves the movement of friendly Henchmen near him with Follow me!, which combined with the Leader Inspire and strategy Rapid Response Training (1/E) can mean finishing with up to 5 counters of movement with a SoB/Police (20 + 4D6 = 24-44 cm) or 6 (20 + 5D6 = 25-50 cm) in the case of Detective GCPD SWAT. Although his Follow me! Is not compatible with Robin Arkham City (cannot suffer the same effect more than once), they can combine together to advance quickly in two independent groups.
On the other hand, he also indirectly enhances the durability of his colleagues in melee (regardless of rank) since his Bluff (1SC) allows you to once per round lower the attack an opponent to 10 cm or less by 1. Although the opponent can still hit the same amount of times (since the counters already assigned are not lost), it does make the hits easier to stop. It combined with Delta SWAT or Arkham Knight's Robin (Tim Drake) can turn them quite hard to be taken down due to the "+2" the win when blocking. Even himself combining it with his Counterattack can make the enemy to think it twice before attacking him.
Teamwork/1 (All) if Batman Arkham Knight is in the band it is a must to take advantage of situations of Numerical Superiority. Between him and the Bat they capitalizes on its "+2" to impact in these situations ("+1" by the situation of numerical superiority, and +1 for his Master Fighter), and also if Robin (Tim Drake Arkham Knight) is in the band. The Bat will not have a rival (with a potential amount of 5+2+1 hits), although this would result in a base cost of 267/$100 between the three.
Finally, Radio ($100) can also be interesting to take advantage of his offensive potential combined with a partner to sidelining an opponent without giving him time to react, although it is true that he is the one to activate first and grab enemies.
In short, this Son of Batman is perfect for reaching a point on the table and becoming immovable through his Defense 4 being Hardened and the conditioning of having Counterattack knowing that his hits will cause double damage. He is also the perfect companion for your allies, for several reasons. The first to improve the capacity of movement with Follow me! That may be further combined with Inspire from the Leader and strategy Rapid Response Training (1/E). The second reason is his Reinforced Gloves and what this means, since they are the ideal candidate to grab enemies and have his companions take advantage of the situation with numerical superiority. Finally his Bluff (1SC) can extend the life of his teammates and himself, facilitating their blocks; and improves his option of Counterattack. As for improvements, perhaps the most important for him to be Arrest ($200), given the nonlethal damage that is capable of causing, and Teamwork/1 (All) if Batman Arkham Knight was in the band with him.