Manchin said if there is movement it'll happen this weekend. I don't think it's a coincidence that Biden's press conference is tomorrow, Thursday. Assuming it's as bad as it will probably be, that's when the dam will break and someone close to him (Pelosi? Schumer?) will tell him it's over. He can obviously stay in, it's his call but...I think he'll be compelled to drop out.
I don't think Obama has much public say in this, after the 2016 fiasco. I don't even think Obama did anything wrong, Biden was prob in no emotional state to run that year after his son died. At the same time...if he did he would have beaten Hillary and Trump.