I’m from the West so I’m not familiar with this program, but given the fact that U Maine does not call its earth science program “geology” (I have no idea about the other schools in Maine), your son may be eligible for the [New England Regional Student Program (RSP)](Tuition Break | New England Board of Higher Education). This could give him a discount at other New England area schools, most notably the University of Vermont, but again, I’m not sure.
Cornell and the University of Southern California are two top schools which not only accept a large number of non lateral transfers, but also have fantastic geology and environmental science programs. Neither offer forestry, and South LA is certainly a far cry from Orono. Indiana University does have a strong geology program at the undergraduate level, although if he doesn’t want to go there, it’s off the table. Your son may be eligible for the University of New Mexico’s Amigo Transfer Scholarship which could bring the COA down to a more manageable level. I don’t believe UNM offers forestry, but its geology program is well resourced and it’s hard to beat an exposed high desert landscape for undergraduate fieldwork opportunities.