Parental Units

I'm not really sure how to start out this random thought I have...So I'm just gonna jump right into it. Lately, I have felt a role reversal between the PU and myself. I feel like I am the mama and M is the daughter (and the same goes with D). If you know me, you know how close I am with my family (extended and immediate), so this isn't an "I hate my family tirade." I wonder just how common my current feelings are. When I talk with M she seems distant and almost juvenile about making plans with me, especially if it doesn't include her "live-in" life partner (which I will actually refer to him as live-in) . Hello M, all events do not HAVE to include live-in! Or when M mentions she is going out of town she acts "bratty" about bringing up Uncle T's gf, stating that the lady "annoys her and doesn't need to be invited because she isn't family."....Real mature M, real mature...
D, on the other hand, seems to be caught up in re-establishing himself at the age of 58. D has dated more women in the past five years than I have had bf's in my entire life. Talk about a player huh? I'm sure things are lonely for him, but when I try to make plans with him he usually already has plans with a lady friend, or just avoids making plans with me all together. (talk about a butt-hurt daughter!)
Maybe M is going through the classic "mid-life crisis." Maybe my feelings stem from not having that special person in my life to lean on, so I am leaning on the PU and not receiving the support I was looking for. I feel selfish for feeling this way about the PU. And I also feel quite juvenile...so maybe the role reversal is just a figment of my immagination. All I know is something just seems off kilter, and I would really appreciate it if things were back to "normal" (whatever normal may be).