Guardian and Estate

"My 9- year old father has passed. If his Mother (my daughter in law) passes...who becomes legal guardian of him and the monitor of her estate. As for my grandson....what's preferred, "A living trust" or a "Will". What's the downside of either one?"

Please clarify your question. Who died? 9 year old father? Do you mean 90 but if so who is mother? If he died you don't need a guardian. do you mean the father died and the child is alive? Please re-submit.