His felony wouldn't be a big deal for employers who would potentially be sending him into people's homes on a regular basis?

I have to strongly disagree with that one.

There are tons of trades that do not require you to ever leave a machine shop or electronics lab. If said person is very capable of coding then I would also strongly encourage them to pursue it, but to convince them that it's their only chance? That statement seemed to be a bit of a stretch. Whatever endeavor though, I wish them luck.

A large percentage of work for plumbers, electricians, HVAC, etc. is in new construction. It might be an issue for some employers, but it won't be for others.

A good friend of mine is a felon and a union master electrician. He makes a decent living, when there's work, and his past doesn't seem to make a difference to his employers. There are definitely many paths one can take; code is a really good one, let's be honest, but it's not the only one.

I believe this is a possibility that is dependent on state licensing laws. In some states, the licensing body may not automatically disqualify felons. In other states, they make exceptions on a case-by-case basis. And in the third category, it is automatically disqualifying. Something to definitely look into, though.