It seems, to me, that most of your hurt and pain stems from money and help that you were promised and feel that you deserve or are entitled to. You say they do this and that for others, and not for you. You ask them for little and they refuse, but give others a lot. Your inheritance was signed away to someone a little less deserving than you....when it was promised to you.
So your hurt and pain all stem from your own personal feelings about things that are going on outside of you. The only way to solve this is to change your own heart and mind.....what you think and feel about what is going on around you.
Stop feeling that you are supposes to get these things. Stop feeling that your parents have to do these things for you. Stop caring about Moneys that they can give you. Stop feeling entitled to anything that they have. Know that your Father in heaven is rich, and that you already have everything you want and need.....so there is no need to worry yourself about the party and inheritance being given to your brother.
Love your parents because of who you are, and who they are, and not for what they have and can give or have given. Expect and want nothing from them and just enjoy their presence for as long as you have left with them.
Once you are able to do this, you will see that you are, in fact, in control of your feelings and emotions, and therefore it was, you, yourself causing the hurt and pain you once attributed to another....