Help advice!?

OK me and my sister are really close! I love her to death! and she is one of my best friend even thought we are 16 years apart! i am 21 years old and she is 37. She has an 8 year old beautifull little girl named Hanna. Hanna has down syndrome. I see the way my sisters struggles EVERYDAY and it hurst me when she gets sad. I have a baby that is 2 years old and i am potty trainig my baby and i feel like i cant talk to her about it cause her 8 years old is not fully potty trained yet due to the fact that she has down symdrome. I feel horrible everytime my baby does something in front of her cause i feel bad her kid doesnt . I want to help my sister cause she has been kinda sad lately about hanna and she cries all the time! I dont know what to do?!??!?!! I LOVE HANNA AND MY SISTER so much. i feel so helpless!Help advice!?
tell your sister god gave her hanna for a reason, and not to be sad she will have another someday and it will be drifferent for her but just tell her to love and watch hanna grow and let her enjoy watching yours grow to , i know how you feel im very close to my sister and it hurts when she is sad , sit your sister down and tell her what i said hanna is a very lucky child to have her for a mother, good luck.Help advice!?
How about if you and your sister sit down together and talk about potty training your child and hers together. Or you guys talk and she can help you with your child in potty training. I hope I helped.