Their doctor is probably going to want them to abstain for a while anyway. I had a miscarriage 6 years ago (baby died at 13 weeks and we found out at 14 weeks). The doctor ordered the normal postpartum abstinence. I seemed to be recovering more or less OK, and then I started having abnormal bleeding. We tried for a pregnancy as soon as the doctor allowed and were successful, but there was a whole lot of medically ordered abstinence before that. The charting was also problematic, very similar to postpartum NFP.
On the psychological side, this is a very traumatic event. Even “just” miscarriage produces a very high percentage of PTSD (40%):
A Disturbing Amount Of Women Experience PTSD After A Miscarriage | SELF
I went to a miscarriage/stillbirth group that helped but I stopped once I got pregnant again, because I knew that it would be hard for a miscarriage sufferer to deal with a pregnant lady. But I needed more support. Being pregnant again helped a lot with recovery, but the pregnancy itself was scary because of previous events and my complications. I don’t think I was really 90% done with miscarriage recovery until I was out of the postpartum period with my youngest–that was well over a year later.
Grief can manifest in ways that aren’t explicitly about the loss. For example, one of the symptoms of my grief was being ANGRY with family members who weren’t supportive. The more I’ve recovered, the more at peace I have been able to be about accepting my relatives for who they are. Don’t let grief hurt your other relationships.
Be very careful about choice of therapist, and make sure that they understand that you need to be able to grieve, but at the same time, keep your ability to function, and keep moving forward. After my miscarriage (and this was especially true after the bleeding, anemia, and birth control pills), I started spiraling down with obsessive negative thinking, anger at my family, and spending literally hours a day howling or weeping once the kids were safely off to school. Not great! I got some relief from the obsessive negativity once I got my doctor to take me off the birth control pills, but I was still not great.
Getting pregnant soon helped a lot. There was still a lot of fear and some negativity, but the pregnancy and new baby helped me a lot in moving forward. I would say that by the time the baby was 4-6 months old, I was doing pretty well.
I have to say that there should be some caution about marital intimacy in this situation. Is the bereaved mom actually OK? Does she actually want to do it? Could sex so soon create a mental link between obsessive grief and marital intimacy? It’s a danger. I had a much less serious issue after my miscarriage where I got flowers a few times to cheer myself up when I was grieving. Believe it or not, doing that created a link in my mind where when I see a bouquet of carnations (like while going through the grocery store), it reminds me of my miscarriage. So, be cautious about not creating a situation where marital sex permanently reminds the grieving mother of the stillbirth and her grief. That would be bad.
Patience now could really pay off.