Let's first address the urgent needs mentioned. Your homeless dad needs immediate help for his heart valve and a shelter from the cold. We pray that God would guide you to the right resources and provide healing for your dad. Remember the words of Jesus in Matthew 25:35-36 (WEB): "For I was hungry and you gave me food. I was thirsty and you gave me a drink. I was a stranger and you welcomed me. I was naked and you clothed me. I was sick and you visited me. I was in prison and you came to me." Help your Dad to receive from Jesus by calling on his name. In addition, seek help from local churches and government agencies for shelter and medical help.
Now, let's address the deeper emotional needs you've expressed. You feel unloved and this is a very painful and real place. It's important to remember that God loves you deeply and unconditionally as mentioned by Jesus Christ. In John 3:16 (WEB) it says, "For God so loved the world, that he gave his one and only Son, that whoever believes in him should not perish, but have eternal life." God sent His Son because He loves you. Always keep the name of Jesus Christ in your prayers for it is the only access by which you can reach the father. This is the foundation of our faith and the most powerful of rebukes to the feelings caused by the devil such as feeling unloved. Any bad things you experience come from the enemy and not from God.
It's clear that you're struggling with feelings of rejection and loneliness, which is very saddening, and we want to address that from a biblical perspective and a rebuke from the enemy. In Zephaniah 3:17 (WEB), it says, "Yahweh, your God, is in the middle of you, a mighty one who will save. He will rejoice over you with joy. He will calm you in his love. He will rejoice over you with singing." God rejoices over you and that is the true source of love which He has explicitly placed His love in you. The fact you are this hurt makes it clear that the natural love given by God in the heart of parents is not being demonstrated to you by your mother. We rebuke the devil and sin in her life causing her to resist God's love and pray that this be removed from her so she can love you correctly.
However, it's also important to understand that God often expresses His love through the hands of other Christians. We can sometimes wrongly attribute the lack of love from others as a lack of love from God, especially when we do not know Jesus or are not regularly going to church or participating in a bible study during the week. Father God, through Jesus The Son, did not design His love this way. In many cases, the lack of love you are feeling is a result of not knowing or walking with Jesus. Come to Jesus and receive love directly and regularly each day.
It's also crucial to address the issue of relationships especially if they are succumbing to sexual partners as fornication or living with another person as husband and wife prior to marriage. Be clear that according to God's Holy laws, this is not to be practiced. If outside of marriage or before marriage, sexual immorality (fornication or adultery) takes place between an individual or couple it is then required that the person or couple repent. The sin of sexual immorality must be confessed and acknowledged and the practice stopped immediately. These practices prevent God from removing the depression and sadness as these are tools of the enemy.
Finally, let's pray together:
Dear Jesus Christ,
We come before You, lifting up this dear one who is feeling so unloved and alone with sadness. We pray that the light of salvation is closer to her and she submits to You now to receive permanent healing and deliverance in Your blessed name Jesus Christ. We ask that You would surround her with Your love and provide her mom with a source to understand her and remove the block in her mother which is preventing her from giving her that love. We pray that You would bring godly people into her life who will love and support her. We ask for deliverance for her father, healing all his infirmities and providing him a saving knowledge of who You are. Help to ensure that she does not get any sinful practices and loves You with an undivided heart. We pray for her grandmother's healing and her mom's healing from asperger syndrome to have a normal relationship with her unloved daughter. In the normal name of Jesus Christ, we pray.
Amen.
Please know that God forbids any sexually active relationship outside marriage and encourages only Godly relationships. That is what is best to seek and desire to feel true love and satisfaction. Add prayer to give mom a godly mind to love her child the way God inhabits her with His Spirit. Continue to care for your grandmother and pray without ceasing for her health. May you seek Jesus to enjoy love, joy, and peace along the journey.