My friends parents wont let us be friends anymore! what do i do?

I recently turned 18. And for the past 2 years, I have been best friends with a younger boy. He is now 14. We met because I dated his sister. I truly do call him my best friend and I think that he is a once in a lifetime friend. Is that weird? We have a lot in common and hang out often. But i do have friends my age i also hang out with. We also text regularly. People seem to think I molest him, but we truly are good friends. Recently, his parents voiced to me that it was weird. But people are friends with younger people all the time. For instance my dad, who is 45 is married to a 30 year old (she is my stepmom) His parents took his phone away and wont allow us to talk. But not talking to him makes me feel depressed. There is a huge hole in my heart where he should be. He calls me the "big brother he always wanted and now got". I dont know what to do without him. And now his sister (my ex) is spreading rumors around that I have d him. This only happened monday,(the 16th) but it has been the longest week of my life. I also found out i am not graduating which was the 18th. Could this be any worse? was i wrong to become friends with him? i have talked to his mom, and she said we can talk about things soon. I was told i am considered part of his family and I would go to them with any problems. But why has this happened? I would never hurt him like that. I havent eaten much and nothing is fun. i am depressed. We were (and remain to be) like brothers, even though his parents severed all contact we had with each other. This has been the worst week of my life!!!! Please help! Sorry if this is too long or anything. And feel free to ask any questions. Thanks!!