If he is using, then you must look out for your little ones first & foremost. I would suggest supervised visits, perhaps with a family member (NOT you) present. Right now my AD (she's in recovery) and her H (she has a NO contact in force) use me as the go between. When it is time for my SIL to pick up or drop off the 1yo, we meet somewhere other than my home (which is where AD is living right now.)