My mother in law wanted to bring my 16 month old son to family event out of town. Due to work issue, me and hubby can't attend the event. Is it safe to baby in that age travelling without parents? And what should i prepare to make my mom in law easier? They stay for 3 days.

If your MIL has been the main caretaker of your child at home, I believe there will be no problem for her to handle your kid as she is familiar with your kid's schedule and temperaments. Thus, you don't have to worry. You can put down a list to remind your MIL on what not to do, e.g. not to feed certain foods especially if your child is allergic to it, activities that you feel not suitable for your kid e.g. outdoor climbing and etc. If you feel uneasy to let your MIL to bring your kid for staycation alone, you can politely tell your MIL about your concerns and get an alternative caretaker to take care of your kid while you are working.