Not only did She abandoned him when he was just a Newborn , leaving him under Shannan's Care (he was just a kid back then) , disobeying Sigurd's Words, when he didn't even know how to take care of himself at that age just because she was so thirsty about Sigurd's Jeigan conqueror of castles Dick and she couldn't wait anymore for him, ditching Seliph like shit and forgetting all about of him just because her lust for Sigurd, not only that - But She never tried to Seek after him when is heavily implied that at some point she Learned about his marriage with Sigurd even tho she never regained back her memories She DID know about having another Son but she never tried to seek after him, Leaving Seliph Dread Alone under Oifey and Shannan's care with 0 Inherited Money from her or even Good Stats, heck, he wasn't even a Pure Blood Naga.
The only time than Deirdre acted like a mother to Seliph was in the After Life being a Ghost, but that probably was Seliph Daydreaming about his parents and how he avenged them after all and fulfilled Sigurd's Dreams
Deirdre got what she deserved for being such a bad mother and this is the root of Sigurd's tragedy and eventually Demise.