So I have family that just moved to Spain. My question is would they be able to send me a box of Cubans without them being confiscated? They live in Barcelona so I'm sure there would be some good cigar shops in that area.

Only a few at a time. I wouldn't try a whole box. Try 3 to 4 first.

ETA: Look up Habanos S.A to find an authorized dealer near them to buy from.

This right there. It's the only way to make sure you get the real deal.

Cubans are scarce in most/all of Europe right now. Was in a few different Habanos shops in Germany and France recently and the selection is nil currently. Prices are also 2-3x a year ago.  You'll have a hard time getting a whole box of real sticks most likely even before customs confiscates them.

If they have to go through Miami expect them to get confiscated.   Right now that port is hot on confiscation.   Other ports are somewhat reliable in getting through.  Reminder.  If you have global entry you can lose it by having goods shipped to you that are banned.    

Spain used to be cheap and reliable for Cubans.  Now, with global pricing, it’s all the same.   Habanos stores are the gold standard but unless you like to pay $500 for a box of mid level Cuban cigars, you aren’t buying Cubans.   Montecristo #2 are around $700 iirc right now.  Cohiba and Trinidad are insanely expensive at this point.