Loss....

One of my friends has two girls who are very similar in age to Regan and Addison. Their father passed away on Friday from complications with MS. I feel that we should talk to Regan especially about the fact that their friends have lost their father. Mostly because I don't want it to come up and be a surprise for her. We took all four girls bowling today and they all had a good time and it didn't come up until I was bringing the girls home and I was glad my children weren't with me. However, next time I may not be so lucky. My biggest concerns are to not make it into a big deal and to not scare my children. The latter being the biggest concern given my recent medical history. Any advice would be appreciated.