I think the day 1 workers bill has been back pedaled on.
Also, a combination of all of these is not looking great at all. 1 issue which an employer knew about and you were actively improving on maybe.
The poster who is a manager whose person is passing probation is an example of where sometimes shit hits the fan and they can see potential. Sickness yes (it's a shitty time of year for illnesses) and if evidenced by drs note or it's very obvious to employer that person is just very unwell then it can be let go but might need monitoring in line with company policy. Same with lateness, it happens (transport strikes, public transport issues or sometimes traffic is really crap and lots of people in the office coming from the same direction are late), it's if everyone else is on time and you alone are late. Childcare issues, again with full transparency with the employer can be overcome but the conversations need to happen preemptively before it's brought up in a performance review.
However, if the person is excellent at their job, not dropping any balls, willing to make time up and generally performing well then arguments can be made to pass probation.
Tbh we are approaching end of business year, conversations about next year's budget, hiring, recruitment for next financial year are going to be happening in the next few weeks. You might already be too late.
You need to address the childcare, do you have a partner (who has built up goodwill with their employer) who can do drop off or cover child illnesses for a few weeks? Or find childcare that is more reliable or starts earlier. Childcare is not a work issue and needs you to find a solution.
Colds and flu, you do sometimes just have to power through a bit. Did you offer to WFH? Did you take a full period off until you were better or did you have a day off, come back and struggle and then need more time off. Under Bradford scale it's better to take the whole week off (even if you poorly on the Monday and Tuesday, feel a bit better on the Wednesday and better on the Thursday) rather than take Monday and Tuesday off, go in Wednesday and then need Thursday off.