I urge you to obtain a copy of 'Outsmart Your Cancer' by Tanya Harter Pierce. She describes upwards of 20 alternative protocols whose cure rates (typically in the 70 - 90% range) leave those offered by conventional medicine eating dust. Hers is also the definitive guide to Protocel, arguably one of the most effective protocols in the treatment of cancer, although it may not be suitable if your dad has an aggressive cancer.

More importantly, these protocols work synergistically with the body's own defence mechanisms rather than trying to clobber the tumor/metastases into submission with toxic regimens that also damage healthy tissue, have horrendous side-effects, and are ultimately inimical to good health and a full recovery. In fact, they are more likely to shorten life, induce more cancer down the line, and most certainly leave the patient in a much worst state, at least in the short term.

If you don't have the time to view the TTAC docu-series, you could do a lot worse than read around the main alt. cancer websites, including TTAC's own:

https://thetruthaboutcancer.com/

and of course the daddy of them all:

http://www.cancertutor.com/

There are many more, but there's plenty there to be getting on with, and I don't want to overwhelm you at this stage. You will find more than sufficient information there to put you on the right path, but I'm pretty sure that a full gastrectomy is not the answer. Quite apart from which, if the cancer has already spread to the lymph system, it's pretty much game over as far as conventional medicine is concerned.

They have nothing to offer that will not make matters worse for your dad, and it's a shame they didn't discover the metastases before they decided it was a good idea to open him up and butcher him. Unfortunately, this level of incompetence that ordinary people have to contend with is quite typical when they put themselves in the hands of the 'white coats'.

Good luck, and by all means keep us posted.