Arnica gel is supposed to be good for bruises. You can usually find it in health food and vitamin stores. Good for soreness too - lots of runners use it. If possible, look for the kind that has the extract as an ingredient, and not a homeopathic formulation/brand. Homeopathic arnica is said not to be as effective. Weleda makes both; the non-homeopathic is the massage oil. I've used it - Weleda's great, but expensive. Fortunately, you only need a little bit. You just gently massage it into the area. Maybe your bf could do that as a little after-care. There are probably other good brands that cost less.
Vitamin C is also recommended. Dr. Weill has a little page about taking care of bruises here: http://www.drweil.com/drw/u/ART02931/Bruises.html