My husband is not very good at D.I.Y but likes to try, do i let him wreck the

With something like that I would put my foot down. Building some cupboards will be a pretty expensive task. If he tries to do it himself and fails to do it right then you might not have the money to get it done professionally. Smaller tasks I might still let him try if they are inexpensive, but I would not let him try an expensive task.