You can do it yourself
Rifles and shotguns are basically simple machines. As with anything mechanical going slow and being organize are the keys to success. Most old hunting rifles and shotguns need only a good cleaning and correct lubing to function fine.
All the information you need to disassemble, clean and reassemble can be found on line. The fine folks here on The Firing Line are very helpful and are willing to share a lifetime of experience.
The sad truth about GOOD Gunsmiths is that they are very hard to find.
If a gunsmith is really good his back log of work could easily be over a year. If gunsmith can get right to it, he very well may be no good.:barf:
Unless you have a personal relationship with a really good gunsmith you are best off to service the weapons yourself.
Please forgive the general nature of the gunsmith statements but it is the truth as I have paid for it.
Once again sorry for your loss,