Re: Stage 4 gastric cancer..

Generally, if a person has months (plural) of estimated time left then there may be a good chance of beating cancer via natural and alternative means.  See for example:

http://curezone.com/forums/fm.asp?i=1606070

I strongly suggest that whatever alternatives/treatments are selected that you encourage your father to go all in and not take half measures in order to have the very best chances of success.