Thanks for posting your query.
If he is on any medications notify them to your physician since some medications would cause decreased libido.
For Premature ejaculation
you can spend more time on foreplay and you can try with start and Squeeze technique, That is at the peak of intercourse you need to remove your penis and control from being ejaculated by pressing with your hand, try it many times during intercourse.
For recovery of libido he should be stress
free and should exercise and take healthy foods and be free from tobacco and alcohol.
Hope I have answered your query.
Wishing you good health.