Is there anything unique you have to prepare for those who are celebrating at this age? I'm looking for something special for my friend's mother

I suggest you focus on keeping the celebrant happy through activities. This is very easy if you have kids attending because of the games you can prepare. Your friend's mother will surely love them.

Here's my personal experience: someone tried to play some 50s and 60s music. Although it's a good idea to play something familiar, it's actually a downer for many. If you want to throw in music to the party, have something light.

Also consider the "Milestone" theme party. For example, silver for those celebrating their 50th birthday. You can complement this by throwing a party themed after the decade A 50s party should be very entertaining especially the jolly music from that era

I think you should not focus mainly on how old they are and what they used to like. Look for a theme based party great for adults. You can have a Luau or just an afternoon barbecue with additional food and guests.