Hello, I am the custodial parent of 2, ages 16 and 14. Their father has not seen them in over 4 years. Is this abandonment? He sent them a letter about 4 years ago, basically disowning them (he signed it, "your former father"). Now, because I contacted him on an unrelated matter (nonpayment on a loan I took out on his behalf), he is (retaliating?) "requesting" that I inform him of the children's after school activities. The children now do not want to see him or have any contact with him (he actually told them they "didn't have to see him if they didn't want to" when they were 10 and 8--I never understood that, and I do not know his reasoning behind doing so). It is sad, all around. However, after all these years, I do not want to go against their wishes. I have talked with them about it, extensively, and they know his contact information is available if they ever want to use it. (Plus, I now think it is in their best interest to abide by their wishes (and maybe that's exactly their father's wishes, too?), given the letter and other things that have happened that have been and are emotionally abusive toward them.)

Do I have any obligation to tell him these things now? Of course, when things were okay between them (the children and their father), he knew of their activities (and even attended, although intermittently, and sometimes, unfortunately, disappointed them by saying he'd be there and then not showing up). He is not asking for visitation, or to spend time with the children. He does have a visitation schedule, but just has not used it in over 4 years.
Thank you for your input.