Overnights with dad

[Wednesdayafternoon]

I posted this in the lone parents page but I'm just reposting here because there doesn't seem to be much tk traffic over there and I just need some reassurance!

I have 2 children under 5. Dad walked out during my second pregnancy so has never live with my youngest. Youngest is 18 months but breast feeds tk sleep, not a good sleeper does not independently sleep. Dad spends 5 hours a week with him. Eldest sleeps over 2 nights which sounds a lot but during that time dad is at work and he's at school.
I think dad is going to start pushing for overnights but child is just not ready for it. He still BF and relies on it. He would be so upset and I would be so concerned about how he would be looked after.
Just needing soem support on this. I'm having terrible anxiety.
History of emotional abuse from ex.
I want to push back until at least 2, or until signs of independent sleep/weaning of breast feeding. Is there any gif ace on this?
I'm so worried :(

Sorry I meant to add that I have been particularly trigged because he's bought my eldest and the youngest matching pjs and my eldest told me. I might be over thinking this (but I don't think I am). He tends to plant seeds with my eldest before speaking to me.

BF is recommended until 2 so I don't plan on stopping u til then, unless of course he stops naturally which is absolutely fine, my eldest stopped naturally at his age now. But that aside, he is so unsettled at night time and he just wants me. He's so dependant on me and I feel so sad about that being taken away :( as he gets older it will get easier but ex will never see it like that. :(

Op you just say no. Simple as that.

Thank you @SleighbellsZ
He just has a way of making me feel like I'm so unreasonable :(
I've spoke to the Hv about this in the past and they've always said what is best for the child, but I get so worried about him starting arguments etc.

I wouldn't entertain it.
I would say no, state my reasons and say we'll see what the situation is in afew month time.
He can't force it.
If he starts, just ignore