Mom Issues....this is kinda long

La
I need some advice...my mom, who I love with all my heart, has been guilting my husband and I for having an easy going baby. She's 5 months old now and so chill and laid back, not terribly fussy, and is a chunky butt. My younger sister has a son who is just over a year old, she's divorced, the dad is a deadbeat, and her son is a handful; constantly moving, fussy as all get out, needs constant entertainment, and my sister cannot handle him. She lives with my parents and they are basically raising her son cuz she works full time. Anytime my mom watches my daughter, for even an hour until my husband can pick her up after work, she gives my husband the guilt trip how "we're so lucky, we have it so easy, Alissa has it so hard". How lucky I am that I was able to pump my breastmilk and alissa had to give Liam formula. How lucky I am that our baby is so chunky and Liam is so skinny (he's just a little dude, he's perfectly healthy), how lucky I am that I can work part time (We're broke as shit, it's not that easy)......Okay, I'm fully aware of this, I'm thankful and never complain about my daughter, I know we got lucky, but I also think it has something to do with the home life and how relaxed the parents are. I never voice this, just smile and nod. But now it's starting to affect my relationship with my mom. I've had it. I will not be made to feel guilty for my sister's bad decisions (not my nephew of course, but we all warned her about her ex husband). I'm worried she'll project this odd jealousy and guilt trip onto my daughter eventually. Any advice how to handle her? I say, 'yes, I know, we're very blessed'. But come on, what am I supposed to say to stop her comments?