Dinner time - generational differences?

I am retired and live with my DS and his family -one DGS who is six. Both DS and DIL are in their forties and work from home. When DS was young, we had dinner at whatever time seemed appropriate - I served the meal and all its components at table and dished out portions, etc. In our present home, I do most of the cooking - I enjoy cooking and have worked hard to hone my skills over the years. DS and DIL are very blasé and erratic about dinner. For example, DIL prepares GS’s dish prior to any of us eating - portioning out what I’ve made for everyone, adding veggies or fruit to his plate, etc. Then she’ll make her own plate. DS will sometimes not even eat at that point and forage in the kitchen much later. Or they’ll want GS to eat around 5:00 (due to bedtime schedule) but DIL will stop and take a shower at 5:00. Silent implication is that DS or I will feed DGS? I realize the challenge of working full time and being a mom - I did it too - but without a “me” to help out in the home. They all love food so it’s not that they “eat to live” - I just don’t get it. I know it’s a little thing and not worth making a big deal out of but just wondering about others’ experiences in a multigenerational household and also about how others would handle it, if at all.