Before I read the part about her still being married I was going to suggest your mom not take out against the boyfriend that which the daughter is guilty of. Meaning, your sister chooses to live with the boyfriend. It’s not like the boyfriend has her held captive or anything, so in light of it being your sister’s willful choice to break the commandment I’m not so sure it would be kosher to let her join the family for thanksgiving but not the boyfriend. If he isn’t welcome, neither should she be - they are behaving as ONE unit.
However, knowing now that she’s also still married, that makes it even more clear to me she shouldn’t be allowed in the home either. Talk about a double whammy! Your mom is already over extending herself by allowing your sister to be a part of the holidays as an example to your siblings. You and she may want to consider counting her blessings and just enjoy the time she’s being given as it is.
I’m just trying to understand how we reconcile this with the other siblings including myself who are sinners.
It’s not your concern to reconcile your sister’s consequences or yours with anyone else in the family. That is your parents’ obligation and theirs alone. Each sibling has their own unique attributes and weaknesses. Wise parents read the signs and adjust accordingly. There really shouldn’t be a one-punishment-fits-all approach in a loving, nurturing home. Trust in your parents to apply the appropriate disciplinary actions necessary for each unique member of the household.
I’m not doing anything as blatant as her. But what about the brother who won’t go to church anymore and the other who won’t have his son baptised. I’m trying to understand where the line is??
Hopefully you are supporting your mom and giving her the gift of not having to discipline you or worry over your soul. You are obviously concerned about the welfare of your family, that is good.
Your mom is being put in a difficult position by your sister and your brother. She is carrying her cross the best she can. Help her carry that cross by not adding to the burden and perhaps by making it clear to your brother and sister that you cannot and will not, in good conscience, side with them against your mother on matters of their spiritual upbringing.
You both need to give your mom a really big hug this Thanksgiving day. Your sister needs to apologize for putting your mom in the position of having to exclude her boyfriend, and she needs to sincerely let your mom know that she will reconsider the decision to live in sin. If she can’t reconsider that position then she can at least promise your mom not to expect the boyfriend to any future family gatherings. She owes your mother the respect she deserves as keeper of your younger siblings’ souls.