I would certainly explore lifestyle solutions first. Whether they should lose weight depends on how much they weight to begin with. It's important that they keep a healthy weight.
Some treatment options include:
Eat smaller more frequent meals.
Stick to a special diet that avoids acid stimulating foods and beverages. Of course, they won't be happy to learn that this list of foods includes ice cream, french fries, and chocolate.
Don't eat within two hours of bedtime.
They could also keep a record of what they eat and when their heartburn is better or worse. This will allow them to determine what food and drink does and doesn't work well with their bodies.