Went through a very similar situation (kid with sensory issues as you describe), which was a very hard time for our family any myself. Also every doctor had a very different theory what was wrong.
What we did in the beginning is establish a plan for getting sleep in shifts. One parent is responsible for the first part of the night, the other for the second part. For a job that requires a lot of concentration, getting little sleep is really hard. Also buy noise canceling headphones / ear protection for yourself and your kid.
Regarding the sensory issues, this got better over time. Not in the way that the sensory issues itself disappeared, but everyone learned to deal with that better, most of all the kid. At some point we also became more accepting with the issues and didn't try to work against them. My kid would only eat 2%-5% of food offered. But she can have her pick and essentially always picks the same foods. Similar with clothes (same sensory issue, it seems. My take it is is actually mixed consistency of materials that is unacceptable). Working against the issues has not proven worth it - in the opposite, I think it's better to be accepting as the child cannot really help itself in this regard.
The sleep issues sorted itself out over time, but that took some years and took quite a heavy toll, unfortunately. Nothing we tried changed the situation, the kid just outgrew the problem at some point.
What we did in the beginning is establish a plan for getting sleep in shifts. One parent is responsible for the first part of the night, the other for the second part. For a job that requires a lot of concentration, getting little sleep is really hard. Also buy noise canceling headphones / ear protection for yourself and your kid.
Regarding the sensory issues, this got better over time. Not in the way that the sensory issues itself disappeared, but everyone learned to deal with that better, most of all the kid. At some point we also became more accepting with the issues and didn't try to work against them. My kid would only eat 2%-5% of food offered. But she can have her pick and essentially always picks the same foods. Similar with clothes (same sensory issue, it seems. My take it is is actually mixed consistency of materials that is unacceptable). Working against the issues has not proven worth it - in the opposite, I think it's better to be accepting as the child cannot really help itself in this regard.
The sleep issues sorted itself out over time, but that took some years and took quite a heavy toll, unfortunately. Nothing we tried changed the situation, the kid just outgrew the problem at some point.