Different time zone will force bf to take care of his responsibilities. No need to contact several times a day if the schedule is solid and nothing urgent happens.

No babysitter is not urgent (his problem to solve), working late when he has to pick up children is also not urgent (his problem to solve). He can plan ahead according to the schedule. Your IM doesn't have to respond immediately to every fart bf sends her (or him, if your brother does it).