What field is he in? 15 years of experience means a lot for a company that don’t have many qualified engineers but for a company that have many experienced engineers they can easily hired a kid out of college for $55K or someone with some experience for around $65-$80K.
Most companies have a range that they are willing to pay. My company pays senior engineers around $75K to $105K. I think $120K is near Manager level salary for most companies. Boeing, Lockeed, Northrop, Raytheon and other aerospace companies pay a lot more (15% to 30% more) but it is also hard to get in.