Internal fixation pain during winter-help pls

Okay so 2 years ago, my boyfriend got in a bad motorcycle wreck and had multiple injuries was wheelchair bound for months etc. he had an internal fixation done and has multiple metal pieces and screws and what not throughout his ankle. Every time it gets cold outside, it causes him constant pain in that ankle. I don’t really know anything about it and I feel if there was something that would help he’d know but maybe there would be answers here? Is there something we can do or get for his ankle to help that? Any tips/tricks or any medical info? Please and thank you!! ❤️