My main reason is as Aioros22 said above. Her being his mom resulted in his death being the most tragic and heroic iteration to date. The betrayal only served to highlight how selfless Jason was. Sure it was contrived, but Jason ended up looking the better man than the rest, DC included, and that's why he's so unconditionally loved by people who are actually aware of the circumstances in and outside the book at that time.
I see. Personally, I found the reveal as something shallow because Sheila was never a character, just a prop to move the story in the direction editorial wanted. Having Katherine being his real mother worked better for me in Lobdell's version of the events.
You know, I was just thinking, this really made for some interesting mirroring situations (something I've noticed that Lobdell has done a lot since this run started).
First and most evident was the one with Bizarro in the tank, awakening, and him being a knock-off of someone he wasn't (Superman) and Jason's whole story of him with the pit and him being a supposedly second-rate Robin.
Then, the whole thing with Bizarro being dangerous but well meant and how Jason too was sort of seen like that.
There is more, but I cannot remember more clear examples, besides these and the one with Bizarro about to kill the henchmen and that henchman who was so in love with his girlfriend.
But now I see another one, with Jason and Willis, and Jason and Bruce, with both as fathers. Until know, Jason though nothing good of Willis; he didn't care for him, even (by this issue's writing, we know that) he was glad he was death, was resentful of him. That's it, until he has come to know about him with the letters, and found out why he did what he did. So now he's denying once again his feelings about it, probably also feeling guilt because he has hated him all this time until now (and because, well, losing another parent that now he knows cared for him hurt).
On the other hand, you have his issues with Bruce when he came back, and probably even now, and how he didn't seem to care or more like want to understand Bruce's feelings until they have some words (and that's still half way happening, the thing about coming to understand Bruce's reasoning and feelings). I guess that's in part why Bruce is the one who's going to deal with the incoming breakdown of Jason (that could easily have been his team mates in any other setting).
Remember how I said that one of the reasons for Jason's self-dishonesty was because he feels guilt because he knows or thinks that he's done something wrong? Here we have another example of it; sure Jason doesn't want to admit that he cares about Willis, because if he cares, then, he is going to feel miserable and feel like a jerk to Willis (as well as losing another parent, as I said). This is cool writing by Lobdell (but he's been quite consistent writing him like this, so it's no surprise, I guess).
I'm also intrigued about that Willis' line about wanting Jason to be a Prince of Gotham. If he really is Solitary, then, I wonder... Maybe all his plotting could be a very complex plan (mixed with a big bit of vengeance) to achieve it?
Thinking back to when Rebirth first started, I'd expected to see Jason mature by gaining different moral standpoints by playing by Batman's rule and working for Black Mask. Now I'm happy to see that he does mature, but as a son starting to understand his fathers' love. Bravo, Mr. Lobdell. You go beyond expectation.
Yeah but as noted, that`s Joker`s story
Frankly, I don`t mind the name of the mother. At this point Catherine has been explored more as a character and she was the mother Jason knew. I simply prefer that he goes to the Middle East after Joker with a solid reason and that`s all Sheila was used for.
Then again, if Catherine does get abducted or something and Jason goes after her, even against Bruce`s orders, that`s fine with me too. Or even some innocent while investigating what Joker is up to. All I am saying is that I rather his death have that touch of heroic poignancy than just defiance and using Catherine is tricky because she`s supposed to have died when he was a pup. All in all, it`s the one thing I feel has been the missed shot for not being directly addressed because the whole rest has been on point.
But really, Jason Todd, "the dammed Prince of Gotham" is almost bar none the finest scene of the issue and Meta rich in commentary.
...But is the same reason.
In the original Jason arrives to Ethiopia following the trace of the women in Willis' life, running into the Joker's activities entirely by accident. In the N52 version Jason arrives to Qurac following the trace of Catherine, falling straight into an ambush set by the Joker.
How exactly does his death hit harder? Jason making a last stand to protect his mother works in the same way on both versions (and in the N52 Jason actually succeded in saving Catherine). The betrayal angle only really works if there's enough build up and Sheila was introduced from the get go as an sleazy individual to which the readers could not create any kind of bonds for her actions to have any emotional weight.
My issue is that Catherine supposely dies in Gotham when he`s a kid by overdosing which was also said in the New52 version. I don`t recall where it was made clear that she indeed lived to be saved later in Qurac outside of Joker`s narration of events.
Catherine being alive and used by the joker is one of the things N52 did that I absolutely hated and I hope not to see it back.
I prefer to have both Sheila and Catherine because Catherine's death also had a big impact on Jason and him suddenly found out that she's actually alive stretches the imagination a bit. As for Sheila, while she's only a prop, Jason's search for her is not out of nowhere but from a need to have a parental figure when things weren't going so well with Bruce. That's a buildup I can get behind. I feel nothing for Sheila but I do for Jason's emotional state and think that it's not that strange for him to immediately latch on her, only to be betrayed.