Frustrated with unhelpful sister

I’m currently 39 weeks pregnant with my third child. I originally moved to the US to be with my husband 11 years ago and I’m now a citizen. My husband has an extremely demanding job and due to this my sister who still lives in my home country offered to fly over to help me out my two older kids leading up to and after new baby’s birth because I’m supposed to be on modified bed rest. We paid for her flight over here and told her we would pay for everything she needed while she was here as a thank you. We picked her up from the airport Saturday and she swore she was going to help me out with my kids, laundry, cooking etc since my husband can’t be around much. It’s now Thursday and all she has done is lounge by the pool, go “explore the area”, ask me to drop her off at tourist spots (she doesn’t drive) and SLEEP. She has been sleeping every second of the day she’s not doing something else and I’m getting increasingly more frustrated. She’s blaming jet lag but has also complaining that she has horrible menstrual cramps and a “sore throat” as reasons why she’s in bed all day. The time difference between the two countries isn’t that extreme so I don’t think she needs 5 days to get over jet lag. Just to point out my sister is older than me and 37 years old and by no means a teenager who is just oblivious. I keep telling her to try and stay awake through out the day so she can sleep through the night but she just goes out on her walks in the morning or lounges by the pool and comes and sleeps from 2pm onwards offering no help what so ever. She also hints that she wants me to take her to do fun things everyday which I cannot do due to the ridiculous heat and the bed rest my doctor has me on. Her behavior is making me slightly uneasy because she was supposed to be our baby sitter when I go into labor and now I feel like I can’t leave my kids with her when I go into labor Incase she sleeps the whole time she’s supposed to be watching them, they’re 2 and 4. On top of everything she smokes like a chimney and sits outside on our front porch and chain smokes all day long (while she’s not sleeping of course). My oldest son is on the spectrum and he has therapists coming in and out of the house all day (my husband and I strictly do not smoke) and it’s so embarrassing for me that every time they come she’s out there smoking or she’s sleeping on our couch in the room they do my sons therapy in. I feel mortified most of the time. What the hell do I do here? I can’t tell her to leave because we bought her a 3 week ticket but I feel like I can’t have her acting this way when I go into labor and have a newborn around, especially with the smoking. Any ideas on how to handle this would be much appreciated, I feel so dumb for flying her here because she hasn’t helped at all only added increased stress to my life.