How to deal with the guilt (I might have caused my fathers death)?

Hello,

my dad (93 years) suffered from heart and kidney disease and was feeling unwell/unrest for a few weeks, especially at night and was not able to sleep. We always kept unecessary medications away from him due his kidney disease. But I thought I was doing him a favor by asking his doctor to prescribe him opipramol. We gave it to him for three days before stopping because he got so weak and sleepy. After stopping he improved for a few days but declined again a bit. My father passed away approx. two weeks after we gave him the first dose of the meds.

Looking back now I regret asking his doctor for medication against his unrest so much, I asked the doctor several times if my dad could take the meds with his kidney issues and the doctor said it was fine. But now I see on the internet that opipramol can have an impact on people with kidney disease. I feel so responsible for my fathers death. I wish I never asked the doctor. I wish I had the doctor around more (didn't have him around a lot because of Covid and the doctor seeing a lot of patients), so he might have noticed that his kidneys weren't strong enough for the medication.

I just don't know what to do.