If I'm 33 weeks pregnant and my father has been getting radiation therapy for brain cancer, is being around him dangerous for my baby?

No. His radiation is done in a closed shielded room. Once he leaves this room he is not radioactive and will not harm you or your baby in any way.
No. The radiation that could harm your developing child is at the facility where he is treated, unless he has had an implant with radoactive sources. Enjoy your father and do not fear his treatment for yourself or your child.
No. External irradiation does not stay in the body so having contact with your father after he has been treated presents no risk to your baby.
No. The most common form of radiation your father is getting for his brain tumor is external beam radiation and usually x-rays are used. In this case, x-rays are only on when the machine is on in the treatment room. When your father leaves the treatment room, he does not carry any radioactivity with him and it is safe for you and the fetus to be around him.;).
No. Most common form of radiation he is getting is external beam radiation, which is typically x-rays. It is only on when the patient is in the room. He does not carry any radioactivity with him. It is safe to be around him even if you are pregnant so long as it is x-rays he is getting.

Related Questions

What are the side effects of radiation therapy for a brain cancer?

Many. Some of the more common side effects from radiation is hair loss, nausea, vomiting, weakness, fatigue, weight loss. It is usually well tolerated although during therapy, you must expect the fatigue and exhaustion associated with radiation therapy.
Depends. Radiation can cause a variety of side effects and complications when treating the brain. These depend on the dose, areas of the brain treated, cancer type, patients' performance status and age, and other treatment factors (surgery, chemo, etc.) the side effects can include: fatigue, memory problems, hormonal dysfunction, visual or hearing changes, hair loss, cognitive changes, edema, necrosis.