With all the stress you've explained which you passed through just to get access to the wallet is believed to be that you needed to help the parents get reached to their sons assets which is stored in the wallet before his demise.
So why don't you do what you can to get access to the wallet as to know if there was coin inside Instead of coming to ask the public here.
I don't also know the kind of suggestion you needed again when your late friends parent has called on you to asiste them recover their sons funds. Or do you mean technically guidelines on how you can maneuver to get access to the wallet so that you can transact with the assets?
Honestly, I worry why the parents would call on you on such case because this is a sensitive view thing if I may say. Does the parent knew your friend was a bitcoin investor? And how do they think you're best convenience to do that task knowing that bitcoin has wallets involving passwords and private keys so how'd the parent think you could have access to such privacy.