You may be able to connect an external keyboard to the laptop, through USB, or some older laptops have connectors for the old round style of keyboard connections. You might also be able to replace the keyboard on the laptop itself. I sure hope you find a way to get your login credentials though!

Edit: this may be silly, but I hope it doesn't rub you the wrong way. Here it is Mother's Day today, and I hope the far more important family that is dear to you brings you joy today. Happy Mother's Day!