cowden disease ritalin

I need advice. My sister is 39 years old and has been diagnosed with Cowden disease and she has breast cancer. This disease is supposed to be inherited: well, our father had a thyroid cancer. He died because of numerous malignancies that were discovered too late.
She was prescribed with Ritalin. This med sound familiar to me, so I did a little research: children with behavioral disorders are on Ritalin. And I also read it causes death with some kids, and in best case just depression etc.
Well my, most important question is, is there a substitute for Ritalin, (not necessarily as a chemical substance)? Is Ritalin the right answer for Cowden disease? Is my sister going to die? Is it possible for me to get Cowden disease?

First of all, I am very sorry to hear about your father, as well as I am to hear for your sister. You must be in great deal of emotional pain.
First of all, to get the biggest burden of your chest… your sister is not going to die, I mean, not necessary. As well as you might know, breast cancer is one of the most curable among cancers, so if discovered early enough, your sister has a great potential to live. The thing with Cowden disease is that mortality rate depends on types and number of malignancy tumors. So, proper disease management is one of the solutions for people with Cowden disease to live. In your sister’s case this is Ritalin. I am also not very sure why Ritalin is popular in Cowden disease management, since doctors are avoiding it at other fields as much as possible and are trying to develop diet that would give hope for non drug alternatives to Ritalin. Yes, I agree totally here with you – Ritalin must be avoided (if that is possible).
And the last answer, there is, I guess, as much possibility for you to get Cowden disease, as it was for your sister. Cowden disease is inherited, as you know, so be grateful if you do not have it. But that, on the other hand, doesn’t mean you won’t get it, as well as it doesn’t mean you will get it. If I were you, I would talk to my doctor about this topic, mention situation in family and, most of all, have regular check ups with my doctor.
I sincerely hope your sister and you shall have a long fulfilling life together!