How to marry grandkids?

I have my daughter married my liege. They have a daughter (my granddaughter). I also have a grandson (from a son, who died).

To become a liege (in the next generation) I want to marry them. But when I offer the liege to arrange a betrothal I can't select my grandson. He is not landed, is 8 year old.

I guess I realized the answer: I can only arrange anything (either marriage or betrothal) for somebody who is in my court.. Am I right?

Solution 1:

You are correct. You can only propose marriages/betrothals when one party is a member of your court (or yourself).

There is, however, an exception to this. You can choose to control who your children marry if they become landed and leave your court (I'm assuming you landed your son and the grandchild inherited from him). I don't know if this applies to dynastic grandchildren but there should be an option on his character view.

It's worth clarifying that the incest involved is not an issue. First cousins can marry in CK2 just fine, although you may end up with funny looking children, especially if you make a habit of marrying cousins.