Depends on whether it's in house or in a firm. If you work in a law firm, expect to average 60 hours a week over the course of a year. You'd be pretty lucky to consistently have one day off. If you work in a large firm, expect to work 70 to 80 hours a week. I have a colleague who literally has not had one day off since she started working last August. That's 10 months without a single day off, including Christmas, birthday, New Year's, etc.
If you work in-house, you work maybe 50 hours a week on average, and typically will have two days off.
Your friend needs to rethink this and consider another line of employment.
The law field is totally saturated and most lawyers after getting their law degree and then pass the bar may find no jobs anywhere;;;;;;;. So your friend thinks, well in lieu of finding a job in a law firm, I will just go solo and bypass finding a job in a law firm.
My husband is semi retired after practicing law for 40 years. He got a job in a firm when he graduated and after 1 year was made a partner and then 10 years later went out and practiced in a sole practice for over 30 years. But he did contracts, criminal, bankruptcy, divorce, custody, social security, personal injury, malpractice, anything that walked into the office that needed to be represented. That is how he learned and also got the experience and knowledge of other lawyers in the law firm that made him better.
In criminal, it takes special skills that require you to know the "system", which means the court, judges, prosecutors and such on what you can and what you cannot do. Many criminals expect you get them off completely, even though the best criminal lawyers in the US cant do it, depending on the crime. In a murder trial or with child molestations, you will get clients you do not want to take or aghast for what they did, but as their lawyer, you have to represent them to the best of your knowledge, once you agree to represent them. We had to take out our address and personal phone number out of the phone book for threats of past clients who claim they will be looking us up when they get out of prison. With no experience, does he plan to go to the police station or to court and look for clients? To get clients, you have to advertise, (costly) or get referrals from other past clients who recommend you.
My husband had only 1 secretary working for him and the cost to run a office cost him $6,000 per month. That was for the secretaries paycheck, rent, utilities, insurance etc. There were some months his secretary made more than him, since many clients did not pay their bills or was waiting for another case to settle. You cant drop a client when they don't pay you, since judges "frown" on this, since you agreed to represent you and if they "stiff" you, that's your problem.
So your friend needs to sit down and calculate the cost of opening an office, plus insurance, continuing education, and then think, how do you get enough from clients to pay those bills. Also have your friend look into advertising, since if no experience or starting out, needs some way to get clients into his office. But advertising is EXPENSIVE. There is one law firm that told my husband that they paid 6 million a year to advertise. Granted that was for a law firm, so would not be surprised that it could cost him thousands a month to advertise.
Oh and if he thinks about working out of his home, he is totally nuts, since if he does pursue only criminal law, does he want them all to know where he lives? He has to have someplace where he can meet clients that is not his home.
If he wants to go into sole practice, he needs to work somewhere 1st, then go out on his own. My husband has NEVER advertised, since all of his practice has been from referrals or prior clients who come back.