There was no objection to her seeing her grandson. At least that I could see. And yes, while I agree she did not know Chad, and may have figured he was like the other DiMeras, the fact remains that Abby loved him, defended him, assured Laura he was not like the rest of the family, plus Laura had to know the lengths Chad went to in order to rescue Abby (and Thomas) from the clutches of Ben.
Jennifer knew all Chad did, how much he loved and cared for her daughter, and had told Laura. Plus Chad had easily agreed to have Lucas & Adrienne move in to help care for the baby. Laura could have just been distant, withholding any niceties, but she did, in my opinion, go overboard.