I would give a flying duck about his feelings.....ask your Dad to help out for the kids and tell him exactly why...
He is too drunk to build a simple sandbox? Give him a choice...either hire someone to do the job correctly or do it by a certain date....or just have Dad come and tell him that you have been asking and getting no results.
Husband sounds like a jerk and a bully...and bullies back down when they are confronted by sober people who stand up to them.
Take the funds out of his drinking budget. Open your own checking account and do not allow him access.
many years ago....I started my "divorce fund" with $7.00 I scarfed off the grocery $$$. and added to it weekly...even pinching $$$ from my husband's wallet when he was passed out drunk..I never thought twice about it.