Hey Sam,
Under regular feeding (daily) and warm temp (>85F), most of my ghost female live for about 5-6 months. I am sure they can live longer when feed sparingly and keep in 70-80F conditions. However, I had one that live for 8 months and lay 14 oothecae.
So keep your male ghost warmer and feed him (force feed if neccesary) regularly. It should take him 3-4 weeks to molt. Also remember to keep him wet and humid (spray daily), that seems to increase my ghost's apetite too.
All the best