My parents aren't religious and I grew up with my mother in an unreligious setting, with a slight view of christianity mostly for tradition. All she did religion wise was to take me with her to church once a year around Christmas for traditions sake, other than that she never talked about god or neither talked about atheism, we just sort of ignored it all.
My wider family however were more religious, my grand parents where Christian though they never really talked about it, we just went to visit them around Christmas for a big enjoyable meal as a buffet style deal which was great. My mothers brother on the other hand was quite religious himself unlike my mother but they tended not to get along too well so we didn't have to deal with him that much. He was a nice man, but his views were a little, excessive, when it came to wanting to demand Christian beliefs.
The most religious of our family was my great uncle who was incredibly Christian, we went around to his mansion on Christmas day and had an absolutely huge meal on the grand table, it was great. He also dressed up as Father Christmas to give us all presents. My mother didn't pretend he was the character herself to us she was quite open with agreeing with us when we said it was our uncle, but regardless it was a family tradition and we continued to do it and let him do what he wished each year, we went along with the prayers he would give before meals and not question the Christian stuff he would say as for once a year it was nice to listen to him as he was close to the only member of our family to be such an adapt Christian and it was kind to let him believe what he wished, as all should do.
Over all my family mostly kept to themselves and we did the same, so the Christian members had their values and we had ours and as far as we know they likely thought we were still Christian, as I suppose we still are, but that they thought we still practiced it.
The single problem we had with our families religion was when they would attempt to force their views, for example when my mother let it slip that I wasn't straight (She isn't exactly the best at keeping her mouth closed) she got quite a lot of hatred from it from her brother and my great Uncle, as they had the view that homosexuality etc. was sinful and you cn sort of see how that went down. But after a while they sort of shut up as they realised yelling at my mother due to my sexual orientation isn't going to do anything, it isn't like she can force me to change it. The best way to deal with that is to just keep our families separate and not talk to each other. Which sadly is what happened after my grand parents died. But alas when the family is as broken as it is then you don't have to worry about religious views of those members anymore I suppose.
