Maybe AC Milan and Werder Bremen have different medical standards. The Italian side was concerned about his past injury history, which includes previous knee injuries and two cruciate ligament tears. This might also be a cover-up of their inability to afford the financial obligations or other reasons. The good part of the story is that Victor Boniface has gotten a deal with a top club. All he needs to do now is work hard to prove AC Milan wrong.
Victor Boniface himself said it during an interview that his past knee injury was the reason why the news was circulating that he failed his medical test with AC Milan I don't think it has something to do with the finance and for Werder Bremen his new team they didn't look at the past record since Boniface wasn't having an current injury issues so I think both teams has different medical standards which is why the he was accepted by the German team. Victor Boniface is a big player he's good in front of goals he only needs to train well and avoid getting injured because if he has serious injuries again in that knee he may find it difficult to get a better offer after his loan deal at Werder Bremen.