If you like Grandpa you will surely like his recordings. Walter Brennan as the Grandpa character made numerous albums in the late '50's and thru the '60s. There is a great podcast called Sounds Like Radio it features popular songs and singers mainly of the '40's thru the early '60's. In addition on some of the episodes the host there, the "Humble Host" will imitate Grandpa and then play one of the Grandpa recordings to go along with his talk. Sounds Like Radio can be heard all for free & no commercials, here:

https://anchor.fm/your-humble-host

Hear Walter Brennan's songs on the following episodes of Sounds Like Radio:
Vol. 14
Vol. 40
Christmas Show Vol. 3
Vol. 46
Vol. 63
Vol. 70
Vol. 73
Christmas Vol. 6
Vol. 90
Vol. 91
Vol. 97