i agree with but i will give you some answers for my perspective. they are only brief.
1) yes this will be a good idea for your friend as it will make the amount of people that buy his artwork of him border. because some people don't like using physical real money to pay for things online. But he will need to understand bitcoin and how to keep things secure. Generally this is good as it will give him an edge over competitors. It will only give him a small edge but nowadays any edge is important.
2) bit pay works well. I believe there is also an option coin base offer.
3) cant really offer many solutions to this but i sell my BTC for cash in person
I hope this helps
Appreciate the responses... will take it slow and careful, and do the research