Well, if Sasaki Roshi has committed sexual misconduct, he is no longer a monk. He has broken his main Bhikshu vows and that vow cannot be regenerated in this life. Unfortunate for him, he has to disrobe, apologize and make amends if he really want to teach. I don't think one need to be a monk to teach the Dharma but one must walk the talk or he cannot move people with his discourses.
It is still not too late but he really needs to make amends before he continues to teach. But one thing I know is that he cannot be a monk anymore. There's no purification or regeneration of that vow. Hence, it is very bad for people to just jump and be a monk without study, contemplation and having the true spirit of renunciation. I know many Abbots of great monasteries tell many people to go home and think about it first before becoming ordained. It is a lifelong commitment and not to be trifled with. However, if one had received the vows, one can still return the vows properly. But one can only retake the vows up to a maximum of 7 times only.
In this day of distraction and spiritual degeneration, it is rare for anyone who sincerely wants to be a monk and uphold their vows all the way. This is especially so for countries where the Dharma is very new or has not taken root into society and culture yet. Therefore, it is important to encourage Dharma teachers to teach and persevere to teach so people appreciate and venerate the Sangha. Eventually, as Dharma takes root, more and more people would renounce worldly life in the total pursuit of Dharma.