Baby sister-in-law

My 65 year old father-in-law and his 30 year old wife have confirmed she is in fact pregnant. Their daughter is due in 3 months. To put into perspective, his oldest child is 38 and my husband (who was the youngest) will be 30 next month. His oldest grandchild is 14 and his youngest (my daughter) is 8 months. This is just plain weird. I just needed to get his off my chest. Thanks for listening.