It's about damn time Abe finally got the chop. He died pitiful like the shitty person that he was. He couldn't accept death until finally Itto was able to calm him down and help him come to terms with it. I'm sure he felt like he could finally accept it if he was being put on the same level as Itto and Retsudō in some type of way.
At first Abe couldn't even bring himself to get on the platform where he must commit seppuku. They had to force him. Then he couldn't bring himself to cut his stomach and cried out like a little bitch. At that point the others were done with his disgraceful behavior and they decided to hold him down and cut his stomach since he wouldn't do it. Even after cutting him, he continued to struggle and refuse. He was even able to get up and use the seppuku blade to kill the three men who were cutting him. They were ordered to cut him down, but even as one who isn't a samurai, he was able to cut them down. It was until Itto came strolling in that Abe finally calmed down. Itto was able to help him accept his fate. Then Itto stuck his hand out for them to bring him a sword and he did what he was known for, beheading people. He swiftly cut off Abe's head, which is kind of funny that Itto was the one to kill him in the end. It's fitting though. Can't wait for Retsudō to finally hear about it.