1998 Mercury Sable

I have a 1998 Mercury Sable. My brake lights stopped working and my gear shift is hard to get out of park. I went and got a new brake sensor and it helped when we first put it in. Now it has stopped working and my brak lights and gear shift are not working again. My cruise control has also stopped working. My brother took a look at it and the wires to the dongle snapped, he wired it back together but now my brake light don't work, but my gear shift is not stuck when the car is off. I can get it out of park. When we turn the car on the gear shift gets stuck in park and is hard to get out of park. Still no brake light. What is wrong and can we fix it?