1.. If you will suffer real hardship from fasting, for which you need to take medication or laxatives by mouth, it is permissible for you not to fast. But if the medication can be taken by injection or by rectal suppositories, this does not invalidate the fast, so in this case it is not permissible to take the medication by mouth, because that breaks the fast in Ramadan with no excuse. 2. If you do not fast, then the matter should be examined further: if the sickness is one from which there is hope of recovery, even after a few months, then in that case you may not fast, and you should make up the fasts later on, when it becomes easy for you to make them up, even if you spread out the days on which you fast, and it is not acceptable for you to feed poor people instead. But if a trustworthy doctor says that it is a sickness from which there is no hope of recovery, and you cannot fast except with real difficulty, because you need to break the fast in order to take medicine, then in this case you should feed one poor person for each day. Please see the long answer.

If your wife who is a new Muslim will not face hardship if she fasts, then it is not permissible for her not to fast. You must explain that to her, and tell her that not fasting is a major sin. She should consult a doctor about the sleep issues and anxiety, and there is nothing wrong with taking medicine for that, if necessary. Whatever she needs of medicine to help her sleep or deal with anxiety, and the like, can be taken at night, so long as that is possible, so that she can maintain her fast and not transgress the sanctity of the month just because of anxiety or anxious thoughts.