one meal or eating in moderation with family and friends wont kill your gains. Your family and friends are things you get once in your life, you eat like 20-30 maybe 40 meals a week, having a cheat or a moderation meal wont kill you unless you are like 2 weeks out from a bodybuilding show or a photoshoot.
Granted the food wont be great, but to be social and interact with your family/friends will be far more important that weighing out food on a scale when you look back you may laugh at your actions. Think about how much one meal will really hurt you in 2 days or maybe a week? your weight will baseline so its not really going to be a major factor.
personally i IF, so some of my meals are large, some are small. If i am going to eat out or with family/friends ill eat lighter in the day (if i eat out later) or vice versa ifi eat out earlier and cut back later, and just move on and try on and focus on hitting your protein intake and overall kcals if possible. if its a cheat meal who cares have one a week and move on, and realize your training and diet the other 6 days of the week and rest of your meals will be in check.