I certainly would not recommend removing the bladder with a diagnosis of "probably invasive".
Get that 2nd opinion and then act and only with a top surgeon. Top surgeons in the field offer the top chances of survival with little or no side effects. Nerve sparing surgery when removing the prostate can save sexual function but there will likely be a time of not functioning (from a couple months to couple years). There are many options for the interim period that his doctor can discuss.
Mike
Age 54
10/31/06 dx CIS (TisG3) non-invasive (at 47)
9/19/08 TURB/TUIP dx Invasive T2G3
10/8/08 RC neobladder(at 49)
2/15/13 T4G3N3M1 distant metastases(at 53)
9/2013 finished chemo -cancer free again
1/2014 ct scan results....distant mets
2/2014 ct result...spread to liver, kidneys, and lymph...