same problem at my farm
Bought a really nice X show gelding (magic mind push) for my boyfriend to ride. He actually looks nearly identical to your friends walker. He does the exact same thing, and forges often. We also had to retrain some of the spook out of him, locally its common for walkers to be trained to be excited when used for showing, but once he figured out we are a relaxed easy going bunch he calmed right down. Went from charging during mounting to calmly standing for mounting and it took just a few trys to get him to understand. We took him to my favorite farrier who is a menonite and has done shoeing his whole life. He rides walkers himself so he knew just what to do for the fix. Pretty much the suggestion of changing angles slowly is what we are doing and it is helping...Magic has been for one shoeing and is due for his second now. also we have been concentrating on gaiting slower but with more collection which is helping. He does still forge but not nearly so bad as when we first got him, his toes were so long he was actually stepping on his front toes!!! At any rate we are happy and he is happy so all is well that ends well. Also we shoed him with kegs with borium since we trail sometimes across roads and rocky dirt trails.