I'll chime in with a few ideas. Loading a boat on a trailer is definitely a challenge in a crosswind, so since my situation is similar, wife wont back the trailer down the ramp, you can try these simple adjustments.
First, make sure you have a long sturdy boat pole, and 2 dock lines at least 25 feet long.
You back the trailer down, then get out of the car, walk to the dock so you will be along side her as she approaches the trailer. If the wind is pushing away from the dock, have lines already on bow and stern, dockside. She tosses you the lines, she nudges the throttle, and you make sure the nose of the boat lines up, uses both lines to "steer" her in.
If the wind will be pushing sideways into the dock instead, you don't really need the lines, just have the boat hook ready to push the boat off enough to get the nose of the boat between the guides. If you dont have the guide post yet, I suggest installing them. Once the bow passes the posts, you just push the stern enough to straighten her out.
Good luck, we have all been there. When the wife is stressed, no one is happy.