How are you now?(不知道你想表达什么,如果问好用这个,如果你确实想知道他在干嘛,用：What are doing now?)You are gonna back to Amercia tomorrow.I wish you a safe trip and please say hello for me to your family.God bless your grandmother will be alright.It's really pity we miss a chance to meet again,but I believe we will meet in the future,right?
Best wishes.
有问题可以补充