13 years is enough to give up, but then, I guess you have to continue the prayers. but from what I know, God chooses to answer prayer at His discretion. The Bible says when we pray according to His will, He answers. However, I guess one day, we will stand before Him and ask him some questions.

However, keep up the faith. I'm not also praying for any material thing, just for mercies and compassion and forgiveness.