sleeping at 3am doesn't seem like she's that lazy.
she just doensn't wanna do things she don't wanna do.

bring change is never easy. finding motivation or target as well.

if she has friends .. maybe that'll help. if she's a neet .. tough luck.

one way is to force her to join you and your parents out for a trip and other things.
in order for her to experience things a bit.
forcing her to go jog .. unless your parents come along ... tough luck, much less request coming from you as an elder sibling.