Welcome to HCM!
From your question the only complains which apparent are--- weakness, and difficulty in taking deep breaths. You have not mentioned any tests reports or any investigation results which might have been done on her. If doctor has adviced her for admission, then he / she must have some valid reason for the same.
I would advice you that either you go with the patient and ask the doctor about what he thinks the problem is and on what basis he thinks so.
Or ---> if there are any test reports / investigations, you need to mention them in question so that a correct advice can be given.
Many times there are cases when patient looks otherwise normal but there are symptoms which necessitate detail evaluation and therefore admission is required.
I'm not saying that your doubts are wrong, but to comment on the situation we need more information as mentioned above.
from the symptoms mentioned, I can say that she should get her complete blood counts, ECG, chest
X Ray, sugar levels,
thyroid levels,
ultra sound abdomen done. These test repost will make things more clear.
Hope this answer guides you to move ahead in right direction.
please meet the doctor and discuss the points and the take a decision
feel free to ask more questions
Dr. Manisha Gopal.