Welcome to the forum
@Jiml
Glad you have joined us!
Some people’s diabetes does evolve and change over time, and can need adjustments to medication.
It sounds like your husband may have some insulin resistance going on? Has he previously been on Metformin? That can help the body use insulin more effectively.
Losing weight, and increasing moderate cardio-style activity can help with insulin sensitivity too.
Don’t think of being put on insulin as any kind of failure. Some T2 pancreases and beta cells / insulin signalling just start to fade over time, and adding exogenous insulin to help out can be just necessary - in exactly the same was as it is needed for T1s with absolute insulin deficiency.
Hope the insulin helps reduce his levels, and you are able to find a balance between adjusted meds, and menu to keep his weight on track.