Yes, they are ascribing an “over all things” awareness to a deceased Christian.
I don’t think it works that way.
I think of the angel saying to Daniel, “But the prince of Persia WITHSTOOD me....”
No, we're not, as explained at length above. How does "over all communications addressed to me" equal "all things". I read my mail. I don't and can't read everyone's mail. I get phone calls when people dial my number. I don't get all phone calls.
And even if were, God forbid, to get everyone's mail, there could be other things of which I was not aware.
And finally, it is by God's grace sustaining my alleged brain that I can read my mail. If it were God's will that I could read everyone's mail (as apportionment no doubt, for my misuses of communication) then He could accomplish it it me.
So the contention that a Saint can hear and pass on all prayers addressed to him or her in no way reasonably implies that the saint is aware of everything or can do everything.