bracelet project. any ideas?

A friend of my family was diagnosed with brain cancer a few months ago. he is divorced and has 3 kids, one out of college, one a sophomore in college, and one an 8th grader. my bff and i decided we want to do a project to raise money for him. we want to make and sell bracelets (the kind you make using string) and give all the proceeds to him. but we have one problem. we know we can easily spread word about it, take orders thru phone and email, and mail the bracelets to customers, but we dont know how to collect the money. it is not very safe to send cash in the mail (it could get stolen) and we can't personally meet up to collect money from the people (we are very busy and there could be too many people). how could we collect the money? anyone have any ideas???