Well, then, how exactly has he developed? He hasn't acquired any solid means of fighting the corpses, even though he has surely seen corpses normally are all about killing people. He hasn't demonstrated of possessing any defenses. In fact, he hasn't apparently even thought how he would act should he be targeted (I don't think it ever visited his mind anybody could target him despite the fact he's always there uselessly hanging around when bad things happen). All he can do is feel sorry for himself and let the current (and the spirit of a cat) take him wherever they intend to take him. The only time he did actually think about something was when he distracted the reflective monster with the phone call, but that was a one time special case only.

The Minai case was just sad. Why the heck did he leave her behind in the first place? He left her behind and went... downtown to hang around?