Advice needed (possible TMI)

My husband and I are TTC. He's had brain surgery and also has low testosterone, so when we BD he has a hard time finishing. I've tried mood music/lighting and he's on Viagra. It still doesn't seem to help. Porn is not for us. Any other ideas? He's in his early 40s and I'm in my early 30s, so I feel a sense of urgency.