This is a great point, but he won't hear it. I've already shared it. We, even as Christians, cannot keep the law in our own strength or as a matter effort or will. As Galatians 5:16 teaches, we will only not fulfill the lusts of the flesh by walking in the Spirit.
No person will be perfect but He can empower us to love His ways
Hebrews 10:16, "“This is the covenant that I shall make with them after those days, says יהוה,
giving My laws into their hearts, and in their minds I shall write them.”
Rather than going I cant you cant we cant, we should be asking for strength to do His will?
John/Yahanan 10:27-30, "My sheep hear My voice, and I know them, and they follow Me. And I give them eternal life, and they will never perish; neither will any man snatch them out of My hand. My Father, Who gave them to Me, is greater than all; and no man is able to snatch them out of My Father's hand: I and My Father are in accord."
John/Yahanan 15:5-16, "I am the vine, you are the branches.
He who abides in Me, and I in him, produces much fruit; but without Me, you can do nothing. If anyone does not abide in Me, he is thrown away like a branch, and is withered; and they gather them and throw them into the fire, and they are burned. If you abide in Me, and letting My words; abide in you, you will ask what you will, and it will be done for you. In this is My Father glorified: when you produce much fruit; and in this way you become My disciples. Just as the Father has loved Me, so have I loved you; continue in My love. If you keep My Commands, you will abide in My love; just as I have kept My Father's Commands, and abide in His love. These things I have spoken to you, that My joy might remain in you, and that your joy might be complete. This is My Command: Love one another as I have loved you. Greater love has no one than this: that one would lay down his life on behalf of his brothers. You are My brothers,
if you do whatever I command you."