Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per the explanation that you have explained it shows that due to slamming of the forearm of your husband there has been soft tissue trauma leading to inflammation of the soft tissues and also spilling of blood from ruptured blood vessels that has been damaged due to injury.. Swelling occurs due to accumulation of blood and inflammatory fluid at the site of injury leading to swelling.. There is also hematoma formation which can stay as a hard lump even when general swelling subsides.. If he is unable to move his forearm then there is a chance of having a bony fracture.. I would advise you to consult an Orthopedician and get evaluated and he can do clinical examination and can also advise you x ray for confirmation.. In case of bony fracture reduction and immobilization will help in healing.. But if there is only soft tissue injury then doing cool compresses over the injury site, applying heparin gel like Thrombophob to reduce bruising and hematoma and applying pain relieving gels like Diclofenac can help.. Hope this helps.. Regards.