Sorry Op for your dad's health condition, i wish him speedy recovery.

Trusting someone or family member with your assets isn't a bad idea but before doing so, there are lots of things to consider.
Anyone can change anytime because he or she is a human, the person you may entrust with your assets may wake up one day with another  motive or thinking to use up your funds either for himself or for the family without thinking or acquiring for the best way it should be used because he does not know the value niether did he work for it. Sometimes due to insufficient knowledge your funds can be misused or they can fall prey to scammers.

In my words, its better you manage your assets by yourself, no one can handle your assets better than you because you know what it's takes to make money but if you feel trusting someone with it is better than that't fine as well.