Children not showing up on membership record.

I have a member that just moved into our ward whose children do not show up on his membership record. He is about to get remarried, and his children live in the same city, but with their mother. I know their records are in their mother's ward, but I was under the impression that his children should show up on his IOS. Any idea why they are not showing up? Assuming this is a mistake, how would I go about correcting this issue on his membership record? What info would I need to track down? I got the names and birthdates for his kids while I was thinking about it. Thanks in advance!

The first thing is to establish that the children are still his, and have not been legally adopted by the ex-wife's new husband.

For things like this, I prefer to call Local Unit Support and see what's is going on. See if the children can be found and if so, who is listed as father.

Note that the church system only has a place for one set of "parents" and is unable to distinguish between biological and adoptive.

Thank you. I will give Local Unit Support a call later this week.