Hello! Thank you for bringing your question to JustAnswer! I'm T-USA and I'll be happy to provide some valuable information!
Junior or Jr. simply means that an individual was born to a person who has the same name. Senior or Sr. almost never appears in someone's name, because there is no way of knowing that there will be a Junior later. In other words, the title of senior is generally applied informally to denote that the parent is the more "senior" person with the same name, while junior is often applied formally or informally to denote that the child the the "junior" person with the same name as his father. In other words, it's used to tell two people, who otherwise have the exact name, apart.
In any case, if "Junior" or "Jr." is part of your son's legal name, he can file a petition for a name change
at the Clerk of Court's Office and, as long as the court doesn't find that he's doing it to defraud someone, the court should generally grant it. There is no legal requirement that Jr. be placed at the end of someone's name.
Alternatively, an individual may generally omit a suffix like Jr., III, IV, etc. without penalty and no legal name change is usually necessary to do that, though some of the most formal documents may still require the full name.
Just let me know if you need any clarification!
I know that this answer may not be entirely what you wanted to hear. However, it's the honest truth and I know you want a truthful answer above all. I rely on your honor to earn my living and I hope that you will click accept so that I am paid for my time and effort spent providing this information. If you don't click accept, I don't get paid anything at all.
If you have a follow-up question, please be sure to ask it using the REPLY feature and I will respond as promptly as possible. In some instances, depending on how long you wait to reply, there may be a delay in my response as I may be taking a necessary break from work.
Thank you again for coming to JustAnswer!