My mom can't sit up without support.
I know that she should be upright when she eats or drinks, but what if she swallows something and it goes into her windpipe? What should I do?
Second question: what if she is eating and gets choked on something? I can't really get behind her to do the Heimlich maneuver, I could try to lean her forward a little and strike the back but my hand would be up high on her back. Would that position force the choked food down further instead of up and out?
Why can't you get your arms around your Mom?
I'd have a talk with her doctor, who may recommend a therapist (maybe occupational, I'm not sure) who can guide you about the best foods to feed your mom and how to position her so that she has the best chance of avoiding choking.
1) Serve food that is palatable. No need for pureed food just yet. Perhaps in the future.
2) Always have a glass of liquid near by, preferably water, when eating.
3) Never let her eat white bread, doughnuts, croissants, danish pastries, even in tiny amounts unless you are standing by with the water. Somehow, these things seem to get stuck in the trachea. Don't worry about the windpipe unless she is taking in air, or talking while eating ( a no no ). This, of course, is the worst thing that can happen. Water will not help if food is trapped in the trachea. The Heimlich, and 911 should be called. Pray, that she can upchuck that piece of food. Choking is my worst nightmare, whether it be me or someone else. I witnessed a tracheotomy once, and it was all hands on deck until an airhole was cut open. Patient came alive after that, but was in need of serious attention by the medical staff.
Elderly people have to be watched.
The other thing to distinguish is between risk of catastrophic choking such as big chunks of unchewed food that can require a Heimlich versus just getting a little bit down the wrong way that just is chronically bad for lung health. Also be aware that if there is no way to get enough liquids in by mouth on any given dysphagia plan, there is an option called the Frazier protocol that not everyone is aware of. Nasal feeding tubes or even G-tubes can be a great idea for some people, but generally are not that great for people whose swallowing problems stem from dementia.