vayigash

The posuk says ויגדו לו לאמר עוד יוסף חי. And they told him saying Yosef is still alive.
The אור החיים asks, how is it possible that Yosef, who knew how much his father loved him, wouldn't have sent a message to his father telling him that he's alive, especially once he was in charge? People kept coming back & forth from canaan to buy food. Wouldn't he have sent a message?
The posuk says ויקרא הוציאו כל איש מעלי: and he called out, remove everyone from before me!
The midrash says that Yosef put himself in grave danger by sending everyone out, for once they were alone & he revealed himself, the brothers could have killed him. Why would he risk his life?
There's a story in שאל אביך ויגדך told about' ר יהושע לייב דיסקין, when he would say his regular shir to his students, his loyal שמש would always bring him a cup of tea in the middle of the shir so that he should have strength, for he was very weak. And since he suffered from low sugar, the שמש would put in a few heaping teaspoons of sugar. One day the students were told that the rebbitzin was agitated & upset, so they went to her to see what was wrong. She said that she found that in place of the sugar container next to the tea, there was a container of salt, & she was worried that the שמש might have put salt into the tea instead of sugar, & it could be life threatening if the Rav drank the tea with heaping teaspoons of salt at a time when he needed extra sugar. The students assured her that there was no way there was salt in the tea, for the Rav drank it like he always did, & there was no change in his expression. Therefore, she must be mistaken.
However, after careful examination, her fears were proven to be true & it was salt instead of sugar. The students went and asked the Rav, how could you do that? Why would you drink the tea with salt when it could have cost you your life!? He answered them that there's a gemara that says נוח לו לאדם שיפיל עצמו לכבשן האש ואל ילבין את פני חבירו ברבים: it's better for a person to throw himself into a fiery furnace than to embarrass his friend in public. So how could I embarrass the שמש who mistakenly put salt instead of sugar??
The אוצרות התורה brings down the פסיקתא that says Yaakov, until the end of his life didn't know how Yosef ended up in egypt. He had no idea that he was sold by his brothers, and not only that, but the whole 17 years that Yaakov lived in egypt, Yosef didn't go visit him. The reason was that he was afraid if he was left alone with his father, Yaakov might ask him how he ended up in egypt, & then he would end up speaking lashon hara & embarrassing his brothers. Therefore, he kept away, & that's why he didn't send a message to his father, for then it might have come out how he got there. And as Rashi says, he sent everyone out when he revealed himself so as not to embarrass his brothers. So even if he put his life in danger, or couldn't tell his father he was alive, or even once he was reunited with his father he couldn't be alone with him, it was all worth it just to avoid embarrassing his brothers. This teaches us how careful we have to be to think of others' feelings & not to embarrass our friends or family!