No, it is completely unethical. Having any sexual encounter with a friend's parent violates multiple boundaries of respect, friendship, and family values. It can cause irreparable damage to the friendship and create a very uncomfortable and immoral situation for all parties involved.
This kind of topic is not suitable for sharing in a general context. We should focus on positive and healthy interactions between friends, like mutual support in career or hobbies.
In a healthy friendship, there should be respect, kindness, and positive shared experiences. Any form of sexual or inappropriate behavior is completely unacceptable. Friends are there to support, have fun with, and grow together in a non - sexual way.
In most cases, it's unethical. A best friend relationship is based on trust, mutual respect, and non - sexual affection. Once sexual activities like a blowjob are involved, it can change the dynamic completely. For example, if one person has different expectations afterwards, it can create a rift. Also, it may make other friends uncomfortable if they find out, and can even lead to the breakdown of the friendship group.
There shouldn't be. Our society values healthy, consensual and proper relationships. A story like this goes against the basic values of respect, propriety and legality in human relationships.