Can quadriplegics still get erections?

I'm considering working for a 52 year old man with home/personal care. He became quadriplegic 30 years ago. Some of the duties include bathing / bathroom / grooming / hygiene. I'm wondering if quadriplegics still get erections, and if so, how to handle the situation without causing extra discomfort, both for him and myself, and still be able to support him as needed.