Especially if they don't completely trust each other, as one can suspect with Graendal and Aran'gar, who never worked together before. Graendal and Sammael were already quite close in the AoL, thus it's not surprising that Graendal would tell him about her lair (contrary to Aran'gar).

I definitely think, though, that it's likely that Graendal and Aran'gar met once or twice in TAR between the prologue of TGS and Graendal's death. However, nothing suggests that Graendal would tell Aran'gar about her lair or that they were closely working together on some project, but just exchanging infos. That Aran'gar lost her power base could make her even less valuable in Graendal's eyes. Probably both were anyway rather busy on their very own plots in the last weeks till Graendal's death so that they didn't see each other that often.

Actually I didn't start the discussion, if Graendal will have a PoV in ToM. Other people suddenly suggested that it's very likely that we will see Graendal again and that she will have a PoV in ToM, although she died, or even claimed that BS stated that we'll see Graendal again, because they obviously misinterpreted BS's comments about the timelines & that Graendal's name will be mentioned in ToM a few times. I just pointed out the reasons then, why it is highly unlikely that Graendal will be seen again, let alone have a PoV in ToM, if she died in TGS. Apparently you agree with this.

As said, I think most likely Aran'gar will muse about Graendal, their last meeting & her death, at whatever location Aran'gar is staying now or during a Forsaken meeting.