First, burglary is two crimes: breaking and entering (i.e. criminal trespass) joined together with another crime, in this case, assault. If there is injury most states increase the penalty. However, there is no way to tell you exactly how much time he will do in this situation. Only the Judge can determine such a thing and due to the fact that he's already done time for similar things, that makes it more likely that he could do more substantial time or any other type of sentence.
Have him see a good lawyer who is local and knows the DA's office and the local Judges.
I practice in California, so my thought are suggestions on how to get a realtively reasonable answer to your questions without undue expense.
The first thing you need to know is not just what your brother is being charged with , but what he is or will be convicted of. There is also the issue of his past. What has he been convicted of before.
You might just call his defense attorney and ask him or her. You might ask the prosecuting attorney. If you know the charges (I do not mean "burglary in the 2nd degree"), the number in the penal code, you can look that up either on line or go to the county law library and the reference clerk should help you.
Washington laws may be very different from those of other states. If your brother has no prior felony convictions and is convicted of a single count of second degree burglary, the court would be required to sentence him 1-3 months in jail. From your facts, it sounds like he could instead be convicted of residential burglary, which carries a standard range sentence of 3-9 months. And if he assaulted your husband while inside the residence he entered illegally, that qualifies as first degree burglary, which carries 15-20 months in prison.
You say he served time for other things before. Those "other things" are counted specifically if they are felonies and would increase the sentence ranges I mention above. Without knowing exactly what they were, I can't provide any more specific answers.
I practice in Skagit County. There can be a big difference in how the Prosecutor and the Court looks at a case of Burglary. They will look at the kind of evidence and quality of evidence against your brother as well as the kind of history he has before deciding what sentence to recommend. You and/or your husband can have input with the prosecutor to assert your wishes. Perhaps treatment, education, or counseling would better serve your brother and the community in the long run? You can speak directly with the prosecutor, hire a good attorney for your brother or speak with his current attorney, or hire an attorney to speak to the prosecutor for you.