My employer is very generous about personal issues, to a point. I have a lot of time accumulated b/c I have worked here for 11 years. However, if I were to be late for work or if it was affecting the quality of my work, they would not be so supportive.
I would make sure you are there, on time, when you are supposto be there. Here the big concern is making concessions for one employee, then you have to do the same for the rest. Think like the boss thinks.
I did tell my boss what was going on. I told him out of respect for him but assured him that I would not let it affect my work and that if I needed to use my time off because of what was going on I would give as much notice as possible. I kept it short and sweet. I know he prefers that.