My husband won’t clean his girls hair, (5yo & 4yo)

Their hair is infested with lice from when they stay at their moms, and it’s so bad. We’ve been together for two years and last year I cleaned their hair literally everyday til it was gone and theyd go with their mom come back and have lice again and it just got to the point where I was tired of it, so I just don’t do it anymore and I ask him all the time when he’s going to clean it and he’ll say tomorrow! Tomorrow comes and he doesn’t do it. No judgment please