Have you told your friend that Bitcoin won't always go up? While waiting for growth, your friend should understand that the money he invests should not be his last penny. And also the importance of storing the seed phrase so as not to lose everything one day.
I saw your post where you are disappointed to report that your amount began to decrease after buying Bitcoin at a not-so-low price. Therefore, encouraging your friend to invest puts some responsibility on you if he is unprepared for volatility.
And before you show your Bitcoin amount, you might want to think about your security. Your friend has been away for a long time, and you don’t know what has changed with him over time.

I don't need to read all this story to know you fake it with your imagination. This quoted part in the story shows you lie about this fiction that does not exists in your real life.

If your story is true, did you friend buy $520 worth of Bitcoin just like that? He didn't inquire more about what this Bitcoin is or how does it work?

Last week, an old friend of mine back then in the university in 2013 who later traveled to Canada to further his studies returned back to the country and yesterday, he coincidentally met my mum at a shopping mall and requested for my contact and my mom gave my number to him so he called and called the nickname that we both normally call ourselves back then in the university days I was so shocked to hear that and I called his original name and he answered and told me he is back from Canada and he requested we meet at a bar immediately.

 So with excitement to hear from an old friend after so many years I just immediately took my bath and zoomed to the bar he directed me, so I got there lo and behold my old time friend. We exchanged pleasantries and started discussing about life and I told him how life have been so uneasy but that I got a job in a factory were am paid $60 for about 2 years now and i told him that my colleague at work introduced me to a forum called bitcointalk where i registered on the forum and learnt a lot of things concerning Bitcoin and i also showed him the amount of bitcoins i have stored in my wallet so far and he became curious to know about bitcoin and i explained everything i know about bitcoin and encouraged him to join me in buying and holdling bitcoin that we are awaiting the bull market after the halving so he became so furious and told me that since he knew me that I don't normally give attention to anything online (internet) but for me to hodl such huge amount of Bitcoins that it means am really serious about it so he became interested and ask me how he can buy Bitcoin as well so I told him step by step on how to buy Bitcoin and he bought Bitcoins worth $520 that is about 0.012194 btc so he told me that he wish to acquire 1 btc so I told him not to worry that he will use the DCA method to buy same amount of bitcoins at different interval then with time he will surely acquire the 1 btc.
My question now is that is it wise that I showed him the amount of Bitcoins I have accumulated before he developed interest?

Never show your balance to others, do you show the balance on your bank account that freely to your friends? If not then why do you treat bitcoin differently? Another problem is that your friend got interested in this market purely for financial gain, and someone like that will most likely not have the ability to hold their coins when the market goes down in value, and finally it does not seem as if you talked to your friend about all the dangers that exist on this market, and if they lose their money they will surely blame you.

Friends are great and friends are great losers so definitely don't show your personal investment amount to anyone. You can tell anyone about Bitcoin whether they are interested in Bitcoin or not, it's their personal matter to show them your personal investment amount to get them interested.  Bitcoin is a potential currency that anyone who avoids will regret in the future. so there is no need to force anyone to join Bitcoin. You continue to invest in Bitcoins while maintaining your privacy. and definitely follow the DCA method

Not safe and prudent to show your wallet to anyone.

After I showed him the amount of Bitcoins I have bought then he just developed interest and since he knew that am not easily convinced on anything concerning the Internet but I told interest in buying and hodling Bitcoin that it's really something that's genuine.

My question now is that is it wise that I showed him the amount of Bitcoins I have accumulated before he developed interest?

If you do this, you will lose your friend and your bitcoins.

Your friend is going to have a plan with some bad guys to attack you on the streets or break into your apartment at night, tie you up, gag you, torture you for three hours, threaten to kill you your family including your dog or cat, eat your food and then force you to send your bitcoin to a address. When you do, they'll disappear for ever. You'll lose so bad that you would never want to talk to anyone about bitcoin.

If you think that your innocent looking friend cannot perpetrate these things, read this  - Physical Bitcoin and Cryptocurrency Attacks that Have Been Reported Worldwide