A word of warning with the horse. Don't coddle him just because he was abused. Be softer, yes, but don't let him get away with things and blame it on his background. Treat him like you would any other horse - work with him on his problems (like being headshy, and trust) and don't play things down as 'getting used to his new home.' I know it's hard but that can and will lead to even worse behavior if he learns he can get away wit hthings because you're soft with him.
That being said YES. Get a new farrier. If he doesn't want to work with any horses that aren't perfect he's in the wrong profession. My farrier was very patient with me and Clem when she was on the verge of a horse breakdown getting her hooves done. And you know what? He finihsed her feet. Didn't hit her. The guy I bought Clem from has ~30 horses, and he trims them himself. One of the horses has a scar across her nose from being smacked with a rasp after pulling a foot away during trimming. It makes me wonder if that's why Clem's not great at standing for trimming.
A horse, especially an abused horse, needs a firm but gentle hand. Don't let her get away with things but geez, don't beat her with a hammer either.