I dive with new divers periodically. The local dive shop will often ask me to buddy up with new divers that show up at shop dives without a buddy. I am always happy to help out, but when it was suggested that I get the DM certification, it was a flat “no”. As a DM you are identifying as a professional and will assume some liability if things go south. You might beat it in court, eventually, but it will be expensive.
As a dive buddy, I am a co-equal and if another diver makes a bad decision, it was his. I might get sued anyway, but I was not marketing myself as a “dive professional.” Even if you never get in the water, the family may decide that your failure to warn them about something could be construed as contributing to an accident, because you were a “professional.” A family that loses its sole source of support may be desperate and look at you as a possible lifeline.
If you get the cert, look at the cost of insurance. I am not a lawyer or a dive professional, but have a vivid imagination.