Thanks to Joseph. I can’t check out my Guard Your Tongue now but a few thoughts:
– is this a situation where it is MANDATORY to give the benefit of the doubt?
– if not, is this is a situation where it is permissible or meritorious to give the benefit of the doubt?
– if not, to whom and under what very limited circumstances is it PERMISSIBLE to say lashon hara, e.g. for a shidduch, or for someone one who eats the person’s food?
– what is the obligation of the friend to first clarify the situation and if necessary give mussar? (Remember the old Hanoch Teller oldie but goodie about a congregant of Rav Schwab’s who had a medical condition necessitating him to eat immediately?)
This is for starters.
A person will very, very, very, very rarely lose out by NOT saying lashon hara, but will much more often lose out by volunteering it.