My son is already 22 years old, can our oldest couple still have a second child?

I think the idea of having a second child is not a problem for couples whose child is already 22 years old, but the idea of having a second child must be discussed with the oldest son beforehand, and if you really want it, then try to convince the oldest son that the oldest son, at 22 years old, is not the same as a small child of 2 years old, and that they are already full-fledged adults, with their own ideas, their own worldviews and their own circle of friends,Parental decisions, both to show a sense of boundaries with their child, but also respect and trust in their child.