As tempted as I am to second-guess the situation, taking the letter at face value, I would just tell the LW and spouse to limit their exposure to their parents, and definitely limit their (hopefully) kid's(s') exposure to them unless there is some dramatic turnaround. It is absolutely okay to not want to babysit or spend a lot of time around grandchildren. It is absolutely not okay to expect your daughter/son to arrange their life plans around your lack of desire to be a grandparent, nor is it okay to advise a woman with existing fertility challenges to wait until they will be even harder to surmount if she doesn't have to or want to based on your desires. Again, taking the letter at face value.