just avoid the friend, or interact less, or divert the subject, or distance yourself.
https://youtu.be/Cf-QZjtr8jo Sincere Christians Investigate Islam Part 1
https://youtu.be/lC7m3Z_Ms-U Sincere Christians Investigate Islam Part 2
You should watch these as well, strengthen your Aqidah, because what we have is absolute, there is no doubt, we have an abundance of evidence and proof, and 1400+ years of scholarship, and we stand upon verified by first hand eye witness reports evidences upon evidences.
read a book, iera.org/jesus link to a free pdf download. Read this book, titled Jesus: Man, Messenger, Messiah. Free pdf download.
If he insists and it falls into theological discussion, challenge his view and leave him speechless, or if you are not equipped for that, simply de-escalate the conversation and connect upon similarities.
Avoid becoming closest/best friends, because clearly he seems pushy on forcing views
Whereas we as Muslims have no need to convince anyone, we couldn't be bothered, we can only present the evidence and nothing more, throughout the Quran the prophet ﷺ is told he is not a keeper over anyone, and the same applies to us, whether they accept or reject our evidence is not relevant to you as a believer, because guidance is in the hands of Allah.