No set time on child visitation

I have a question about our child custody papers. I have a 6 yr old with my ex husband, and we DO have child custody papers drawn up, but at the time my son was only 2. Since then he’s started school etc. Well, in it it states his dad is to have him every other weekend, and one night a week for a supper visit. It is NOT a set day of the week, nor is there specified times. Well, this is starting to interfere with my sons bedtime etc. EXAMPLE, last night he picked him up about 4pm, and I told him to have him home and fed supper, & bathed by 7:30-8. Well, no sign of them, so I messaged him, @ 8:05 he had just left his house, and had to stop and get gas, he did not arrive home until a little after 8:30, then my son informs me he did NOT do his homework, and naturally he’s wide awake, and not wanting to go to bed. Well, then this morning he did NOT want to get up etc. What can I do in this even it happens again? I have discussed this numerous times with his dad, and all he says is I have custody of him, it’s my problem to deal with him in the mornings etc. I see it as his dad being vindictive, and irresponsible. Also, we have been meeting 1/2 way from where we live, and I have wanted to stop that as well, because it always seems he’s late showing up to meet me, or wants me to drop him off there on Fridays when its his turn to get him…I understand sometimes he gets off work a lil late (by this I mean 6-7) but my thoughts on that as well as he can just get him Sat then, or not get him at all. Of course I am the bad one in the situation as always, he fusses at me, cusses me out etc, telling me I am selfish etc. It’s not about me at all…it’s the fact of I see this being a one sided deal…I also see it effecting my son. Any advice on what I can legally do to solve this and be fair.

You may want to consider filing a motion for judicial assistance in order to have the court set some parameters for the issues that were left vague in the original order. I don’t see that there has been a substantial change in circumstances warranting a new custodial schedule, but certainly it would help to have set times for the exchanges and transportation put in place.