On the derived $\pi$-length of a finite $\pi$-solvable group with a given $\pi$-Hall subgroup

Let $G_\pi$ be a $\pi$-Hall subgroup of a finite $\pi$-solvable group $G$, and let $M$ be a maximal subgroup of $G_\pi$. We find estimates for the derived $\pi$-length $l^a_\pi(G)$ of $G$ depending on the structure of the subgroups $G_\pi$ or $M$. We consider the situation where all proper subgroups in these subgroups are abelian or nilpotent. In particular, we prove that $l_\pi^a(G)\le5$ if $M$ is a minimal nonnilpotent group.