tl;dr: Upper management urges me to warn my team against participating in a fundraiser for a former boss, who owns our direct competition.
Locale: US. Bob is my former mentor and CEO of a very small (<20 people) IT company. Work for Bob was my second gig after coming to the US and I loved every aspect of it. Bob was a great manager and a superb mentor. in general, he has a reputation of not only an expert but also a cool boss.
I can't stress how much I enjoyed work for Bob. Still, I've had outgrown his shop and become a team leader in much larger (>2000 people) company. In principle, we are his competition, but due to the sheer size difference, it shouldn't matter.
Recently I have heard that Bob has very serious health problems. Right now, he is unable to work and experiences financial stress. His spouse established a fundraiser for him. One of my teammates, also a former employee of Bob had told us about this during the lunch break. Recently, my supervisor informed me that she knows about this conversation and feels it is not acceptable. According to her, Bob is our competition and we shouldn't help him. I should neither allow my team to talk about the fundraiser nor support it myself. She also asked me to talk about the situation with my subordinate who mentioned the fundraiser. She wants me to warn him that such behavior may lead to more serious consequences.
I found this request quite shocking as the help is not related to Bob’s company, but to Bob himself. I do not want to talk to my team about this situation, but going against the will of my manager is unreasonable. On the other hand, I do like Bob and want to help him as much I can.
What would be the most professional way to proceed in this situation?
EDIT 1: The fundraiser allows anonymous donations.
EDIT 2: I work in California.