Firstly you need to make sure he is taking steroids, as it would be seen as a great insult to accuse someone that has worked hard to develop their body naturally.
If he is taking steroids he will be aware of effects and is able to accept future issues as a side effect. You should not get involved but be at hand if he ever needs help. Cases like this you might cause more issues then good. Am assuming this Singh wouldn’t want people to know that he is using steroids and by you approaching him may cause hostility.
I know a lot of people train lift weights and use supplements to help develop muscle mass certain things that you should be aware of. All whey proteins contain animal fats/ingredients.
Your body naturally produces more testosterone when you work out your legs.
You can buy natural green products such as
Tribulus ( A Plant that enhances testosterone)
ZMA which is a mineral compound.
You wont see the same effects as steroids but then again you wont get the long term side effects.
Like everything in life you only get out what you put in, cheating only get you so far!
Instead of whey use soy’er protein, takes longer to digest therefore your body is in a longer anabolic state and is also natural no animal / man made ingredients.