Rav Yishak Yosef, in his Yalkut Yosef (starting on p. 501), discusses the Halachot regarding waking one’s father and mother. He addresses the case of a father who generally makes a point of adhering to the view of the Magen Abraham (Rabbi Abraham Gombiner, Poland, 1637-1683) concerning the final time for the recitation of Shema. The final time according to the Magen Abraham’s view is earlier than the final time as determined by the Vilna Gaon (Rabbi Eliyahu of Vilna, 1720-1797). The Yalkut Yosef writes that if the father is sleeping as the time of the Magen Abraham approaches, and the child could assume that the father would feel disappointed if he did not recite Shema by that time, then he should wake his father. If, however, the father occasionally misses the time of the Magen Abraham, relying instead on the view of the Vilna Gaon, then the child should not awaken the father, unless the father had explicitly requested to be awakened at that time.
If a parent receives a phone call while he or she sleeps, the child should not wake up the parent, unless he knows with the certainty that the parent would be distressed over having missed the call. Thus, for example, if the call is from a distinguished person, such as a prominent Rabbi, and the child can assume that the parent would want to be woken to answer the call, then he may wake the parent. This applies to visits, as well. If somebody comes to the door and asks to see a parent who is sleeping, the child should wake the parent only if he knows with certainty that the parent would otherwise be distressed. Likewise, if a needy person or charity collector comes to the door, a child should wake his parent only if he knows with certainty that the parent would prefer to perform this Misva personally. If he has any doubt in this regard, however, he should not wake the parent.
If nine men are assembled in the synagogue and need one’s father – who had already prayed – to complete the Minyan, the child may wake the father if he knows that the father would want to be woken to perform this Misva.
In all cases where Halacha allows one to wake his parent, he should preferably have somebody else wake the parent, rather than do so himself.
One should not bring his father or mother news that would make him/her feel distressed, unless it is necessary for the parent to hear the news. If a child receives word that his parent has been diagnosed with a serious illness, Heaven forbid, and the parent is still unaware of the diagnosis, he should not bring the news to the parent, and should instead have somebody else report the distressing news.
Summary: One should not wake his father or mother, except in situations where he knows for certain that the parent would want to be woken. Even in such cases, it is preferable to have somebody else wake the parent. One should not relay distressing news to his parents unless it is important for them to hear the information.