OK, here's what I recommend. Take your order to the police station and ask about what happened. You want to see the report involving the police attending the residence for a domestic when your children were there. You have sole custody and you're entitled to information about your children. You especially want to know whether any charges were laid, or any no contact / restraining orders in place (which is technically public information) especially regarding the children (which you definitely have a right to know about).
The police likely won't give you a copy of the file, and because of privacy legislation they shouldn't. But you might be able to bluff your way into some info. Maybe they'll show you the file or read to you sections that relate to the children. That would be a good start. Ask if CFS was contacted about the incident, and whether or not it's the police's policy to contact CFS when children are present or involved in violence in the home. Perhaps you'll get some results from that approach; it's not guaranteed but worth a try. Don't go in there screeching, but be assertive and firm. Don't do it by phone.
After that, go to CFS with any information you have gleaned from the police. Go to their intake department, ask about whether the police made a call to them about the incident. If so, ask for that information. If not, ask if the police are supposed to contact CFS when there's domestic violence involving alcohol and children in the home. Again, don't be screeching about the children being in danger, but be firm and assertive. Don't do it by phone either.
Depending on what you find out, you can then consider father's request. If you want to buy more time or put reasonable conditions on it, you could insist on some things and father's commitment in writing, perhaps including:
-That there be no consumption of alcohol by him or the girlfriend or anyone else in the home while the kids are there and 12 hours prior to the start of his weekend.
-That the girlfriend not be present during his access.
-That he do some relapse prevention and/or anger management and/or couples counselling with the girlfriend and/or some joint counselling with the the children to talk about what happened and why it was wrong and that it won't happen again.
-That he sign releases allowing you access to the police records regarding the October 2015 incident, and to any and all CFS records about the children to see if anyone has made any referrals to that agency.
-That he work up to weekends. He's hardly seeing the kids now, and going back to full overnight weekends isn't going to happen; he's got to work up to it by taking all the kids for full daytime access every second Saturday or something to make sure that the kids are comfortable and to demonstrate his commitment.
You could also ask why he now wants full weekends after a year. What's changed on his end?
Remember that he has a right of access. Don't forget that. But it's access as you two agree upon, so if you can't agree then it doesn't happen. And if he doesn't like it he can take you back to court. And he's entitled to if he doesn't like the conditions you give him, so of course you have try to make your conditions reasonable.
Thus your question of what's reasonable is an excellent question. While some of the conditions I mentioned above would likely be considered reasonable, insisting on them all would probably not be. A good idea would be to get a lawyer to write to him about what you've decided as conditions. Then your ex is more likely to take it seriously, and you'll have the lawyer's opinion about what would be considered reasonable by the family courts in your area.
Does that make sense? I'll await your question or comment. If I've answered you fully may I please have a positive service rating? Ratings are how I get credit from the site for helping its customers. I'd appreciate it very much.