I take psychiatric medicines and the doctor forbade me to fast. I live in Switzerland and the doctor is Swiss. The medicines gives a lot hunger and thirst. Must I fast Ramadan even I'm sick?
Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
At first, you have to look for a Muslim trustworthy doctor, since the opinion of such a doctor only is accepted in this case, i.e. breaking the fast due to sickness. If you do not find that, then you can follow the opinion of the Swiss doctor you mentioned in your question as long as he is an expert doctor.
Then, you have to make up the days you break when you become able to do so. But, if your sickness lasts for a long period (chronic), you have to feed one poor person for every broken day with a Mudd of food (measure equals 750 grams of rice …).
Allah knows best.
You can search for fatwa through many choices