Praying parents back into the church

I’m wondering if there are faithful Catholics here who have had fallen away parents return to the church? My elderly parents are fallen away Catholics. They divorced when I was a teen and remarried other people. They have no interest in seeking an annulment. When I visit I can’t help but feel discouraged. I know time is always limited, but I feel like I have an even shorter window now that they’re in their seventies.

I’m married with five beautiful children whom I homeschool. My children also pray for their conversion. I have only one sibling, a nun who is missioned in another country. We both pray for our parents to return to the church. I know she especially makes sacrifices. I’ve found the surrender novena to be encouraging. I’m also wondering if there’s something my sister and I should pray together.

I know this is in God’s hands, but if anyone has any suggestions, I would love to hear it. For the most part I feel trust, but I think (and maybe it’s related to peri-menopause), there are moments when I feel like I really despair over this. Please be kind.