I agree with everyone. Just be yourselves, living a life of example is really the best way to handle this. If the Lord wants you to do more, you'll know it.
However, if the relationship between your husband and his friend gets in the way of your walk or causes problems, you may need to limit contact with him. I believe that as Christians we cannot, nor should we ever, cut ourselves off completely from non-believers but sometimes these relationships can affect us adversely if we're not careful. This has been the case in my own life.
My three closest friends from high school are extremely liberal, we'll say non-church goers (because I think they believe in God). They think my views and beliefs are silly and believe that this is a lack of intellect on my part. Sometimes I can deal with these issues, sometimes it's just too hurtful. For example, one had a miscarriage and was most concerned about losing pay at work from being out sick. For me, I had to hang up the phone because I was crying at the loss of her child. I've found recently, that I've had to limit my contact with them because they're not respectful of my views and I find it hurtful and damaging to my own walk.
On the other hand, I also have three college friends who are pretty liberal, non-church goers who are VERY respectful of my views. I have no problem whatsoever in my relationship with this group of friends as far as my own walk is concerned and can talk with them daily, often witnessing through my own experiences without even realizing it.
Hopefully, you'll find in your own experience since the seeds of faith were already planted in your husband's friend as a child, that your positive influence will help him to grow again and turn toward the Lord.
