Rock Climbing with Wife turned into Disaster. Need Advice

So recently I've gotten into climbing, going with a friend every weekend to climb or rappel at the local state park. My wife takes interest in my hobbies and wanted to come with us one weekend so we brought her along.

We were having a go at a route we frequent while showing my wife the basics, she got really engaged and we even let her practice belaying. Point of information: my wife weighs roughly 240 lbs and I weigh 150. So while she made a fantastic belayer, we were cautious about letting her climb.

Despite my concerns she really wanted to give climbing a go so we obliged. Her harness was a very tight fit and we actually had to cut parts of it and reattach with quickdraws so she could slip it on, she also refused to wear a helmet.

She managed to lift herself above one foothold (about 3 feet) before collapsing. She fell like a rock, shooting me in the air before I had time to react. Because I didnt want to get hurt I left go of the rope but unfortunately she landed on a root and hurt her head.

She is still very excited about climbing and we're already planning our next route. Our question is how can she safely climb despite our weight difference? I'm working on gaining weight and getting cleats but I don't think that will be enough.

Thanks for the time.