All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
There is no doubt that the father has a great right on his children as he is a cause of bringing them into this life and he suffered in nurturing them and spending on them. It is for this reason that it is an obligation in Islam to be kind and dutiful to him. Allaah Says (what means): {And We have enjoined upon man goodness to parents.} [Quran 29:8] You should therefore treat your father well. Also, you should be careful of anything that might make him angry and be careful of cutting relations with him if he mistreats you. It is an obligation to be kind and dutiful to him under all circumstances.
However, if there is anything for which he requires advice, then one has to choose the appropriate time for doing so and seek the help of the pious and righteous people who are most likely to influence him. It is not an obligation that this role should be done by one of the children as in general the parents do not listen to the advice of their children because they see them as younger and therefore less experienced.
As regards what you have mentioned that your father is planning to marry you off to someone you do not wish to marry, then you should know that it is not permissible for a guardian to marry off an adult sane virgin woman to someone she does not like.
However, if it is possible for the woman to please her guardian by accepting to marry the person whom he wishes if he is a religious man with good moral conduct, then this is something good and she will be rewarded for it. However, if the woman does not know this person, she may pray the Istikhaarah (guidance seeking) prayer and seek the advice of the people who know him.
However, if the woman is not willing to marry this person and she does not want him, then she may try as much as possible to convince her guardian and please him. If he is convinced, then all perfect praise be to Allaah, but otherwise, she is not obliged to obey him because it is her who will suffer any harm or disadvantages that would occur due to the marriage.
Allaah Knows best.